Dear Alison,
Thanks for your efforts, I agree with the general approach you suggest.
For 4.5, you have omitted "direct" before "radiative_effect" .... is this a typo?
For this variable, I thing we need to retain the "assuming_clear_sky" for consistency with the surface fields, i.e.
toa_longwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky (W m-2).
For the surface fields we have both the direct radiative effect of dust in normal sky (4.3, 4.6) and the clear sky equivalent (4.4, 4.7).
To answer your questions:
(1) 4.5 should be the direct effect.
(2) Isn't there is some ambiguity in "radiative forcing", in that it can include both the direct and indirect effects? The indirect effect is something which cannot, as far as I know, be calculated as a diagnostic without performing two simulations, so we would not expect it in the CMIP data request. As the direct effect is more precise, I think we should use that here and add a definition of the form:
"X_direct_radiative_effect" refers to instantaneous radiative impact of X on the Earth's energy balance, excluding secondary effects such as changes in cloud cover which may be caused by X.
regards,
Martin
________________________________
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Alison Pamment - UKRI STFC <alison.pamment at stfc.ac.uk>
Sent: 23 May 2018 12:56
To: 'Karl Taylor'; cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] PMIP: standard names for the CMIP6 data request: tws, lighning flashes, wetland emissions, etc
Dear Karl, Martin and Jonathan,
I've put some more thought into the aerosol radiative names needed for PMIP. Thanks all for the discussion of these names - it's taken a little while, but I think I understand them now :)
It seems to me that the proposed quantities are intended to be _only_ that part of the radiative flux that is caused by the presence of aerosol. (Or we could say it is the _change_ in flux caused by the presence of aerosol). This is definitely not the same quantity as the total surface/toa fluxes and so shouldn't have the same standard name. It is also not the same quantity as the total flux calculated after changing one aspect of the model e.g. clear sky, clean sky, etc. We could describe the relationship between the various diagnostics as: clear sky flux = flux_assuming_clear_clean_sky + flux_due_to_aerosols_assuming_clear_sky. We already have names for total fluxes. Clean_clear_sky fluxes are proposed for RFMIP and the ones being proposed for PMIP are the complement of those. A similar argument could be made for the all sky fluxes.
Following this line of reasoning, isn't it the case that all these PMIP quantities can be regarded as aerosol radiative forcings, or at least radiative effects? If so, we should name them accordingly. We have existing names for cloud radiative forcing, which we call 'radiative_effect'. For example,
toa_cloud_radiative_effect (Wm-2)
'"toa" means top of atmosphere. Cloud radiative effect is also commonly known as "cloud radiative forcing". It is the sum of the quantities with standard names toa_shortwave_cloud_radiative_effect and toa_longwave_cloud_radiative_effect.'
We also have toa_longwave_cloud_radiative_effect and toa_shortwave_cloud_radiative_effect. When I first discussed the PMIP names with Martin (offline) I think I said that we don't have any existing names for 'forcing' but actually we do! We have a whole collection of names such as:
toa_instantaneous_radiative_forcing (Wm-2)
'"toa" means top of atmosphere. Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.).'
There are also longwave and shortwave versions of this, plus some names for tropopause forcing.
We haven't discussed proposal 4.5 much yet, but Martin has described it as
>> (4.5) CMIP6 short name lwtoacsdust. Clear Sky Longwave Radiative Forcing due to Dust at TOA.
And I suggested we call it
toa_longwave_dust_ambient_aerosol_particles_radiative_effect (W m-2) '
"toa" means top of atmosphere. The term "longwave" means longwave radiation. Dust radiative effect is also commonly known as "dust radiative forcing". It is the difference in radiative flux resulting from the presence of dust aerosol particles, i.e. it is the difference between toa_outgoing_longwave_flux_assuming_clear_sky and toa outgoing longwave flux assuming a clear sky (i.e. no clouds) and no dust. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the st
andard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature". A phrase "assuming_condition" indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition.'
The other names are surface quantities but I think it makes sense to treat them in a similar way to 4.5. Martin's suggestion of 'aerosol_direct_effect' then fits in quite naturally. We'd have something like:
4.3 surface_[net_downward]_longwave_dust_ambient_aerosol_particles_direct_radiative_effect (W m-2)
4.4 surface_[net_downward]_longwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky (W m-2)
4.6 surface_[net_downward]_shortwave_dust_ambient_aerosol_particles_direct_radiative_effect (W m-2)
4.7 surface_[net_downward]_shortwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky (W m-2)
I've put 'net downward' in brackets, but I think we probably do need to keep that in so that the sign convention is clear. I've made an example definition for 4.3 and the others would be similar:
surface_[net_downward]_longwave_dust_ambient_aerosol_particles_direct_radiative_effect (W m-2)
'The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). The term "longwave" means longwave radiation. Aerosol radiative effect is also commonly known as "aerosol radiative forcing". It is the difference in radiative flux resulting from the presence of aerosol particles. The "direct radiative effect" of aerosol means its impact on radiative transfer calculations through scattering and absorbtion processes. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have ta
ken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature".'
Are we going along the right lines now?
This raises a couple of other questions:
(1) Is the toa flux in 4.5 a total radiative effect, or should that one be a 'direct' effect too? If it's the total effect, do we need a sentence in the definition to explain that?
(2) We have some existing forcing names and some for radiative effect. We could think about standardising on one syntax or we could simply add a sentence to the forcing name definitions saying something like ' "Radiative forcing" is also sometimes referred to as "radiative effect".' Personally, I'd be okay with the second option but what do others think? (This issue need not slow down the introduction of the PMIP names - I can update existing names at a later date, but it would be helpful if we can decide on a general approach).
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
-----Original Message-----
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> On Behalf Of Karl Taylor
Sent: 21 May 2018 17:06
To: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] PMIP: standard names for the CMIP6 data request: tws, lighning flashes, wetland emissions, etc
Dear Martin,
Sorry, there is no accepted "rule" for deciding under which circumstances a change in experiment conditions should be described in the standard_name. I listed two possible ways we could draw the line (which I subsequently referred to as "rules"). I would favor drawing the line using "rule 2". I haven't heard anyone say we shouldn't at least draw the line using "rule 1".
I think we should try to define a rule we can live with, not just proceed on a case-by-case basis as they come up. If we decide to include special names for each "perturbed radiation" calculation, we could potentially expand the radiation-related standard names
substantially. If you and Martin think that's o.k. (and we don't hear
any strong objections from others, I don't mind.
best regards,
Karl
On 5/21/18 8:30 AM, Jonathan Gregory wrote:
> Dear Martin
>
> If the new terms are calculated by extra radiation calls, could they
> be phrased with "assuming", like the clear-sky ones?
>
> Cheers
>
> Jonathan
>
> ----- Forwarded message from Martin Juckes - UKRI STFC
> <martin.juckes at stfc.ac.uk> -----
>
>> Date: Mon, 21 May 2018 11:18:05 +0000
>> From: Martin Juckes - UKRI STFC <martin.juckes at stfc.ac.uk>
>> To: Karl Taylor <taylor13 at llnl.gov>, Jonathan Gregory
>> <j.m.gregory at reading.ac.uk>, "cf-metadata at cgd.ucar.edu"
>> <cf-metadata at cgd.ucar.edu>
>> CC: "Yves.Balkanski at lsce.ipsl.fr" <Yves.Balkanski at lsce.ipsl.fr>
>> Subject: Re: [CF-metadata] PMIP: standard names for the CMIP6 data request:
>> tws, lighning flashes, wetland emissions, etc
>>
>> Dear Karl,
>>
>>
>> I wasn't aware of the rule (2) you refer to .. there may be a number of other terms that need to be reconsidered if we intend to impose this.
>>
>>
>> There is a disagreement between Jonathan and yourself about he nature of the clear sky radiative fluxes: Jonathan has expressed the opinion that the clear sky fluxes are, like the proposed "due_to_ambient_aerosol_.." terms, calculated by running the radiative transfer module in a diagnostic model. This view is supported by the Ghan 2013 paper (https://www.atmos-chem-phys.net/13/9971/2013/acp-13-9971-2013.pdf ) which describes the relationship between the clear sky fluxes and a new set of "clean-clear-sky" diagnostics. New standard names for these "clean-clear-sky" fluxes have been in the CF Editor for some time (e.g. downwelling_shortwave_flux_in_air_assuming_clean_clear_sky -- http://cfeditor.ceda.ac.uk/proposal/1488 ).
>>
>>
>> If Jonathan is correct, then the proposed new terms are consistent
>> with the approach used for clear sky fluxes,
>>
>>
>> regards,
>>
>> Martin
>>
>>
>>
>>
>> ________________________________
>> From: Karl Taylor <taylor13 at llnl.gov>
>> Sent: 18 May 2018 17:18
>> To: Juckes, Martin (STFC,RAL,RALSP)
>> Subject: Re: [CF-metadata] PMIP: standard names for the CMIP6 data
>> request: tws, lighning flashes, wetland emissions, etc
>>
>> Hi Martin and Jonathan,
>>
>> That is my understanding too, it is a extra calculation done at run time purely for diagnostic purposes; it may not be required in performing a simulation. So this puts it in a category between:
>>
>> 1) A simple change in a variable from one simulation of a coupled model to another (e.g., the difference in temperature between a "historical" run and a control run). We generally do not assign a new standard_name for such differences.
>>
>> and
>>
>> 2) Prognostic and diagnostic variables calculated during run time and needed in order to run the model or to compare the model with observations. We generally do assign specific standard_names to each of these quantities.
>>
>> The proposal is to relax rule 2) to include additional diagnostic quantities. If we want to consider a difference between two calculations performed by a model (in this case a radiation code), does it warrant a new standard_name?
>>
>> In the CMIP6 archive we must surely assign it a different variable name (for uniqueness), and I would think we would give it a nice descriptive long name indicating the information about what it is (e.g., "due to"), but there is no fundamental reason to assign it a unique standard_name, and I wonder if we should draw the line as described in 2) above.
>>
>> There is precedence for *not* assigning a new standard name for a
>> diagnostic quantity not needed to run the model. In the CMIP6
>> request, we ask for
>>
>> variable name standard_name long_name
>> ------------------- ------------------------- --------------------------
>> clt cloud_area_fraction Total Cloud Cover Percentage
>> cltcalipso cloud_area_fraction CALIPSO Total Cloud Cover Percentage
>>
>> best regards,
>> Karl
>>
>>
>> On 5/18/18 7:38 AM, Martin Juckes - UKRI STFC wrote:
>>
>> Dear Jonathan,
>>
>>
>> I believe that they are repeat calculations in the model, as you
>> suggest. They have been requested for PMIP by Yves Balkanski, so Yves
>> may be able to comment more on this point (the question refers to
>> swsrfasdust and related variables),
>>
>>
>> regards,
>>
>> Martin
>>
>>
>> ________________________________
>> From: CF-metadata
>> <cf-metadata-bounces at cgd.ucar.edu><mailto:cf-metadata-bounces at cgd.uca
>> r.edu> on behalf of Jonathan Gregory
>> <j.m.gregory at reading.ac.uk><mailto:j.m.gregory at reading.ac.uk>
>> Sent: 18 May 2018 13:31
>> To: cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>
>> Subject: [CF-metadata] PMIP: standard names for the CMIP6 data
>> request: tws, lighning flashes, wetland emissions, etc
>>
>> Dear Martin and Karl
>>
>>
>>
>> In CMIP6, we want, for each experiment, surface net downward longwave flux (rls) and the two aerosol sub-components, surface net downward longwave flux due to the ambient aerosol direct effect and surface net downward longwave flux due to dust in clear sky. I feel that this falls comfortably into the existing usage for the "due_to" construction.
>>
>>
>> I agree that if these fluxes mean the part of the net downward flux
>> LW flux that is emitted by the ambient aerosol or by the dust you
>> could say it was "due to". How are they calculated? Are there
>> repeated radiation calculations in the model, like for the clear-sky fluxes?
>>
>> Best wishes
>>
>> Jonathan
>>
>>
>>
>> ________________________________
>> From: Karl Taylor <taylor13 at llnl.gov><mailto:taylor13 at llnl.gov>
>> Sent: 17 May 2018 15:58
>> To: Juckes, Martin (STFC,RAL,RALSP); Pamment, Alison
>> (STFC,RAL,RALSP);
>> cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>;
>> Yves.Balkanski at lsce.ipsl.fr<mailto:Yves.Balkanski at lsce.ipsl.fr>
>> Cc: Jean-Yves Peterschmitt
>> Subject: Re: [CF-metadata] PMIP: standard names for the CMIP6 data
>> request: tws, lighning flashes, wetland emissions, etc
>>
>> Dear Alison, Martin, and all
>>
>> On the last point commented on by Martin:
>>
>> "4.3-4.7 Perturbed radiation calculations"
>>
>> I wonder if it is wise to assign a new name every time experiment
>> conditions change. I would limit names to quantities that are
>> calculated independently by a physics model or that can be measured
>> more-or-less directly using instruments. A quantity that is obtained
>> by subtraction or by redoing a calculation with altered conditions
>> could be described as being "due to X" where X is whatever condition
>> was changed, but I'm afraid these names will multiply endlessly.
>>
>> I think it is fine that we include "clear-sky fluxes of radiation"
>> because they are both measured and must be calculated as part of a
>> normal radiation calculation.
>>
>> I would be unhappy with "temperature_change_due_to_greenhouse_gases"
>> and 'temperature_change_due_to_aerosols" and
>> "temperature_change_due_to_solar_variability", etc. Each of these can
>> be obtained by carefully designed experiments and they do contribute
>> individually to the total temperature change found in a historical
>> run, but it in all cases I think the standard_name (air_temperature,
>> or
>> surface_air_temperature) should identify the quantity.
>>
>> Similarly, I would leave out "due to ..." in the definitions proposed.
>> [I realize this is a judgement call about where to draw the line.]
>>
>> best regards,
>> Karl
>>
>>
>>
>> On 5/17/18 2:54 AM, Martin Juckes - UKRI STFC wrote:
>>
>>
>> Dear Alison,
>>
>>
>> Thanks .. some answers and comments below. I've copied Yves Balkanski in to comment on the dust deposition parameters (4.1-4.2) [Yves, this discussion is trying clarify the definition of parameters depdust anf sedustCI, and to define appropriate standard names for these variables].
>>
>>
>> 1.1 I?m waiting for some feedback from LS3MIP to clarify intention
>> regarding land ice;
>>
>>
>> 1.2 Thanks, frequency_of_lightning_flashes_per_unit_area (m-2 s-1)
>> and propsoed definition are good;
>>
>>
>> 2.1
>> surface_net_upward_mass_flux_of_methane_due_to_emission_from_wetland_
>> biological_processes (kg m-2 s-1) and proposed definition are good;
>>
>>
>> 3 Stratospheric depths: thanks.
>>
>>
>> 4.1-4.2 Dust deposition
>>
>> I?ve checked the initial request from PMIP and it now looks clear to
>> me that the dry aerosol mass flux is wanted for these variables. I?ve
>> copied Yves Balkanski in to this discussion, as he specified these
>> parameters for PMIP and may wish to comment. For mass budgets of
>> aerosol amounts it makes more sense to deal with dry aerosol fluxes,
>> rather than ambient mass which depends on local conditions. The
>> definition of ?dry aerosol? is, I believe, intended to refer to
>> aerosol propoerties applied to aerosol particles which have been
>> dehydrated, either physically or conceptually, in order to make the
>> required measurement, not to aerosols which are naturally free of
>> moisture in the atmosphere. I accept your other suggestions, hence
>>
>> 4.1:
>> tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due
>> _to_deposition (kg m-2 s-1) [depdust]
>>
>> 4.2:
>> tendency_of_atmosphere_mass_content_of_insoluble_dust_dry_aerosol_par
>> ticles_due_to_deposition (kg m-2 s-1) [sedustCI]
>>
>> 4.3-4.7 Perturbed radiation calculations
>>
>> As I understand it, terms or the form radiative flux due to X refer to the result of a perturbed radiation calculation, with other factors, such as atmospheric and surface temperature and reflectivity held constant. Hence, the upwelling longwave flux will be unchanged, as you suggest, but not the upwelling shortwave flux: the upwelling flux will change when the downwelling flux is modified by changing the radiation calculation. There is a slight problem with the approach here, in that the "due_to_X" construction is intended to be used to distinguish contributions from different processes "X", but "ambient_aerosol" is not strictly a process: the process is ambient aerosol contributions to the radiative transfer calculations. In proposing these names I stayed with the compact form, which has been used previously, rather than trying to expand to indicate the process itself explicitly in the standard name. The questions raised here make me wonder whether we should be more expansive. In the scientific litera
ture the terms "direct effect" and "indirect effect" are now well established, with "direct effect" referring to the impact of aerosol on the radiative transfer calculation through scattering and absorbtion. The indirect effect refers to other changes caused by aerosol through processes such as cloud seeding. Hence, I suggest sticking with the "net_downward" formulation (it is required for shortwave, and using the same approach for longwave looks neater to me), and appending "direct_effect":
>> 4.3
>> surface_net_downward_longwave_flux_in_air_due_to_ambient_aerosol_dire
>> ct_effect (W m-2)
>> 4.4
>> surface_net_downward_longwave_flux_in_air_due_to_dust_ambient_aerosol
>> _direct_effect_assuming_clear_sky (W m-2)
>> 4.6
>> surface_net_downward_shortwave_flux_in_air_due_to_ambient_aerosol_dir
>> ect_effect (W m-2)
>> 4.7
>> surface_net_downward_shortwave_flux_in_air_due_to_dust_ambient_aeroso
>> l_direct_effect_assuming_clear_sky (W m-2) Regards,
>>
>> Martin
>>
>> ________________________________
>> From: Pamment, Alison (STFC,RAL,RALSP)
>> Sent: 14 May 2018 16:21
>> To: Pamment, Alison (STFC,RAL,RALSP); Juckes, Martin
>> (STFC,RAL,RALSP);
>> cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>
>> Cc: Jean-Yves Peterschmitt
>> Subject: RE: PMIP: standard names for the CMIP6 data request: tws,
>> lighning flashes, wetland emissions, etc
>>
>> Dear Martin and Jonathan,
>>
>> While going through the VolMIP names I realised I had made a mistake
>> in some of my suggestions for this group of PMIP names. I suggested
>> 4.3, 4.4, 4.6 and 4.7 should not be surface_net_downward_fluxes but
>> simply surface_downward ones. If we agree on this approach they
>> should actually say downwelling, not downward, so they would be
>> 4.3 surface_downwelling_longwave_flux_in_air_due_to_ambient_aerosol
>> (W m-2)
>> 4.4
>> surface_downwelling_longwave_flux_in_air_due_to_dust_ambient_aerosol_
>> assuming_clear_sky (W m-2)
>> 4.6 surface_downwelling_shortwave_flux_in_air_due_to_ambient_aerosol
>> (W m-2)
>> 4.7
>> surface_downwelling_shortwave_flux_in_air_due_to_dust_ambient_aerosol_assuming_clear_sky (W m-2) and the definitions would need to be adjusted accordingly.
>>
>> Best wishes,
>> Alison
>>
>> ------
>> Alison Pamment Tel: +44 1235 778065
>> NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk<mailto:alison.pamment at stfc.ac.uk>
>> STFC Rutherford Appleton Laboratory
>> R25, 2.22
>> Harwell Oxford, Didcot, OX11 0QX, U.K.
>>
>> -----Original Message-----
>> From: CF-metadata
>> <cf-metadata-bounces at cgd.ucar.edu><mailto:cf-metadata-bounces at cgd.uca
>> r.edu> On Behalf Of Alison Pamment - UKRI STFC
>> Sent: 14 May 2018 08:47
>> To: Juckes, Martin (STFC,RAL,RALSP)
>> <martin.juckes at stfc.ac.uk><mailto:martin.juckes at stfc.ac.uk>;
>> cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>
>> Cc: Jean-Yves Peterschmitt
>> <Jean-Yves.Peterschmitt at lsce.ipsl.fr><mailto:Jean-Yves.Peterschmitt at l
>> sce.ipsl.fr>
>> Subject: Re: [CF-metadata] PMIP: standard names for the CMIP6 data
>> request: tws, lighning flashes, wetland emissions, etc
>>
>> Dear Martin and Jonathan,
>>
>> Thank you for proposing this set of names and for the comments received so far. The proposals look good - I have accepted a couple that seem straight forward and I think we can agree the rest quite quickly. Please have a look through my comments on the individual names and let me know what you think.
>>
>>
>>
>> (1.1) CMIP6 short name mrtws. Terrestrial Water Storage
>> land_based_water_amount (kg m-2) 'The quantity with standard name
>> land_based_water_amount, often known as "Terrestrial Water Storage",
>> includes surface water (water in rivers, wetlands, lakes, snow, vegetation and reservoirs) and subsurface water (soil moisture, groundwater).'
>>
>>
>> Jonathan has suggested land_water_amount for consistency with land_ice names. I agree this is a good idea, especially if the term "land water" is already in general use. Regarding the definition, it seems we should also include at least some elements of land_ice within land_water, but there is a question as to whether this would also include floating ice shelves and/or ice sheets.
>>
>> This name is still under discussion.
>>
>>
>>
>> (1.2) CMIP6 short name Flashrate. Lightning flash rate cf.
>> number_of_icebergs_per_unit_area; number_of_observations There are no
>> standard names for frequency of events, but we can adapt the "number_of_" construction.
>>
>> Proposed name:
>> frequency_of_lightning_flash_per_unit_area (km-2 s-1) 'A lightning
>> flash is a compound event, usually consists of several discharges.'
>>
>>
>> Jonathan has suggested, and Martin has agreed to, frequency_of_lightning_flashes_per_unit_area. I agree that name looks fine. I think the canonical units should probably by m-2 s-1, and I've added a sentence about frequency to the definition:
>>
>> frequency_of_lightning_flashes_per_unit_area (m-2 s-1) 'A lightning flash is a compound event, usually consisting of several discharges. Frequency is the number of oscillations of a wave, or the number of occurrences of an event, per unit time.'
>>
>> Is this okay? This name is still under discussion.
>>
>> 2. Wetland parameters
>> ===================
>>
>>
>>
>> (2.1) wetlandCH4 Grid averaged methane emissions from wetlands
>> surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biol
>> o gical_production is recently approved. In other existing names we
>> have "biological_processes" to cover production and consumption. The
>> CF area type table now includes the area type "wetland". This term is
>> intended to be the sum of the production term described by surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_production and a consumption term (surface_downward_mass_flux_of_methane_due_to_emission_from_wetland_biological_consumption).
>> Proposed name:
>> surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biol
>> o gical_processes (kg m-2 s-1) 'The emission from biological
>> processes is the net emission resulting from combined production and consumption.'
>>
>>
>> Usually for a net flux, we say that in the name, so this one should be:
>> surface_net_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_processes (kg m-2 s-1) ' "Upward" indicates a vector component which is positive when directed upward (negative downward). A net upward flux is the difference between the flux from below (upward) and the flux from above (downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. Methane is a member of the group of hydrocarbons known as alkanes. There are standard names for the alkane group as well as for some of the individual species. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. the surface of the earth). "Emission" is a pro
cess entirely distinct from "re-emission" which is used in some standard names. W etlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season. The precise conditions under which wetlands produce and consume methane can vary between models. The quantity with standard name surface_net_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_processes is the difference between the upward and downward surface fluxes of methane which have standard names surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_production and surface_downward_mass_flux_of_methane_due_to_wetland_biological_consumption, respectively.'
>>
>> I have adapted the sentence we usually use to describe net radiation to describe fluxes instead. We have existing standard names for both the production and consumption terms so I have added cross-references to those. The rest of the definition was constructed from existing text.
>>
>> Is this okay? This name is still under discussion.
>>
>> 3. Stratospheric optical depths
>>
>>
>>
>> Following existing name stratosphere_mole_content_of_nitrogen_dioxide
>> and
>> atmosphere_absorption_optical_thickness_due_to_dust_ambient_aerosol_p
>> a
>> rticles and
>> atmosphere_optical_thickness_due_to_sulfate_ambient_aerosol_particles
>>
>> (3.1) CMIP6 short name: od550aerso Stratospheric Optical depth at 550
>> nm (all aerosols) 2D-field (here we limit the computation of OD to
>> the stratosphere only)
>>
>> Proposed name:
>> stratosphere_optical_thickness_due_to_ambient_aerosol_particles (1)
>>
>>
>> 'The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-"optical_thickness") on traversing the path. A coordinate variable of radiation_wavelength or radiation_frequency can be specified to indicate that the optical thickness applies at specific wavelengths or frequencies. The stratosphere optical thickness applies to radiation passing through the atmosphere layer between the tropopause and stratopause. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative hum idity that exists in
its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature".'
>>
>> The name and units look fine and I have constructed the definition from existing text. This name is accepted for publication in the standard name table and will be added in the May update.
>>
>>
>>
>> (3.2) CMIP6 short name od550so4so. Stratospheric Optical depth at
>> 550 nm (sulphate only) 2D-field (here we limit the computation of OD
>> to the stratosphere only)
>>
>> Proposed name:
>> stratosphere_optical_thickness_due_to_sulfate_ambient_aerosol_particl
>> e
>> s (1)
>>
>>
>> 'The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-"optical_thickness") on traversing the path. A coordinate variable of radiation_wavelength or radiation_frequency can be specified to indicate that the optical thickness applies at specific wavelengths or frequencies. The stratosphere optical thickness applies to radiation passing through the atmosphere layer between the tropopause and stratopause. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative hum idity that exists in
its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature".'
>>
>> The name and units look fine and I have constructed the definition from existing text. This name is accepted for publication in the standard name table and will be added in the May update.
>>
>> 4. Dust
>>
>>
>>
>> Based on
>> atmosphere_absorption_optical_thickness_due_to_dust_ambient_aerosol_p
>> ar
>> ticles
>>
>> (4.1) CMIP6 short name depdust. Total Deposition Rate of Dust
>>
>> Proposed name:
>> surface_downward_mass_flux_of_dust_ambient_aerosol_particles (kg m-2
>> s-1) It might make more sense to ask for mass flux of dry aerosols here.
>>
>>
>> We have the following existing names:
>> tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due
>> _to_dry_deposition
>> tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due
>> _to_gravitational_settling
>> tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due
>> _to_turbulent_deposition
>> tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_wet_deposition.
>> Dry_deposition is defined as the sum of gravitational_settling and turbulent_deposition. The sum of dry_deposition and wet_deposition is just 'deposition' which we use in some existing nitrogen_compound names. The quantity you are proposing looks to me like it should be the sum of all deposition terms and for consistency with the existing names it should be expressed as a tendency_of_atmosphere_mass_content. Putting all this together, I think the name should be written as:
>> tendency_of_atmosphere_mass_content_of_dust_ambient_aerosol_particles_due_to_deposition (kg m-2 s-1) 'The phrase "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including "content_of_atmosphere_layer" are used. The mass is the total mass of the particles. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of th
e particles. To specify the relative humidity and temperature at which the quan tity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature". The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Deposition" is the sum of wet and dry deposition.'
>>
>> The definition was constructed from existing text.
>>
>> I note your comment about whether this should be a 'dry' or 'ambient' aerosol name - please see my comment on proposal 4.2 which leads me to think this one should indeed be 'ambient'.
>>
>>
>>
>> (4.2) CMIP6 short name sedustCI. Sedimentation Flux of dust mode
>> coarse insoluble The adjective "coarse" has been left out of the standard name because it appears to be implicit in the term "dust".
>>
>> Proposed name:
>> surface_downward_mass_flux_of_insoluble_dust_ambient_aerosol_particle
>> s
>> (kg m-2 s-1)
>>
>>
>> The fact that this one says 'insoluble' makes me think this is what we would usually call 'dry_aerosol', i.e. it hasn't (or can't) take up water from the atmosphere. That would then suggest that proposal 4.1 is referring to ambient aerosol because it doesn't say 'insoluble'. Do others agree with that line of reasoning? We have existing names for 'coarse_mode' aerosol particles, defined as having a diameter greater than 1 micrometre, and 'nucleation_mode' aerosol particles, defined as having a diameter of less than 3 micrometres. I am not expert enough to advise on whether 'dust' would always be considered 'coarse' so I don't know whether it's necessary to include that in the name. Again we should write the name as a tendency_of_atmosphere_mass_content for consistency with existing names. This would lead us to:
>>
>> tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_deposition (kg m-2 s-1) 'The phrase "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including "content_of_atmosphere_layer" are used. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. Aerosol particles take up ambient water (a process known as hygroscopic growth) depending on the relative humidity and the composition of the particles. "Dry aerosol particles" means aerosol particles without any water uptake. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting
the phrase. "Deposition" is the sum of wet and dry deposition.'
>>
>> The definition was constructed from existing text.
>>
>> Writing the name this way means we then have a pair of names, 4.1 and 4.2, for deposition of ambient and dry dust aerosol particles, respectively. Are these okay?
>>
>>
>>
>> (4.3) CMIP6 short name lwsrfasdust. All-sky Surface Longwave
>> radiative flux due to Dust
>>
>> Proposed name:
>> surface_net_downward_longwave_flux_due_to_dust_ambient_aerosol (W
>> m-2)
>>
>>
>> If this is a surface flux due to dust, does it make sense to describe it as net flux? A net downward flux would be the difference between the downwelling flux and the upwelling flux at the surface. I assume that the models don't calculate the upwelling flux due solely to dust lying on the ground(!) so I think this name should be described simply as a surface_downward flux:
>> surface_downward_longwave_flux_due_to_ambient_aerosol (W m-2) 'The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "longwave" means longwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through h
ygroscopic growth. The extent of hygrosc opic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature".'
>>
>> The definition was constructed from existing text.
>>
>> Okay?
>>
>>
>>
>> (4.4) CMIP6 short name lwsrfcsdust. Clear-sky Surface Longwave
>> radiative flux due to Dust
>>
>> Proposed name:
>> surface_net_downward_longwave_flux_due_to_dust_ambient_aerosol_assumi
>> n
>> g_clear_sky (W m-2)
>>
>>
>> As for proposal 4.3, I think this one should be a downward, rather than net downward, flux:
>> surface_downward_longwave_flux_due_to_dust_ambient_aerosol_assuming_clear_sky (W m-2) 'The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "longwave" means longwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself."Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up
ambient water through hygroscopic growth. The extent of hygrosco pic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature". A phrase "assuming_condition" indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition.'
>>
>> Okay?
>>
>>
>>
>> (4.5) CMIP6 short name lwtoacsdust. Clear Sky Longwave Radiative
>> Forcing due to Dust at TOA
>>
>> Proposed name:
>> toa_net_downward_longwave_flux_due_to_dust_ambient_aerosol_assuming_c
>> l
>> ear_sky (W m-2)
>>
>>
>> The CMIP6 description says this one is a radiative forcing, rather than a flux. Looking at existing names, I see that we have a three that include the term 'cloud_radiative_effect', e.g. toa_longwave_cloud_radiative_effect, defined as longwave cloud radiative forcing. I suggest we follow the pattern of the existing names and write this one as:
>> toa_longwave_dust_ambient_aerosol_particles_radiative_effect (W m-2) ' "toa" means top of atmosphere. The term "longwave" means longwave radiation. Dust radiative effect is also commonly known as "dust radiative forcing". It is the difference in radiative flux resulting from the presence of dust aerosol particles, i.e. it is the difference between toa_outgoing_longwave_flux_assuming_clear_sky and toa outgoing longwave flux assuming a clear sky (i.e. no clouds) and no dust. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. To specify the r
elative humidity and temperature at which the q uantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature". A phrase "assuming_condition" indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition.'
>>
>> Is this okay?
>>
>>
>>
>> (4.6) CMIP6 short name swsrfasdust. All-sky Surface Shortwave
>> radiative flux due to Dust
>>
>> As (4.3), but for shortwave.
>>
>>
>> To be consistent with 4.3, this one would be:
>> surface_downward_shortwave_flux_due_to_ambient_aerosol (W m-2) 'The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "shortwave" means shortwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water throug
h hygroscopic growth. The extent of hygro scopic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature".'
>>
>> Okay?
>>
>>
>>
>> (4.7) CMIP6 short name swsrfcsdust. Clear-sky Surface Shortwave
>> radiative flux due to Dust
>>
>> As (4.4), but for shortwave.
>>
>>
>> To be consistent with 4.4, this one would be:
>> surface_downward_shortwave_flux_due_to_dust_ambient_aerosol_assuming_clear_sky (W m-2) ' The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "shortwave" means shortwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have take
n up ambient water through hygroscopic growth. The extent of hygr oscopic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature". A phrase "assuming_condition" indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition.'
>>
>> Okay?
>>
>> Best wishes,
>> Alison
>>
>> ------
>> Alison Pamment Tel: +44 1235 778065
>> NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk<mailto:alison.pamment at stfc.ac.uk>
>> STFC Rutherford Appleton Laboratory
>> R25, 2.22
>> Harwell Oxford, Didcot, OX11 0QX, U.K.
>>
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Received on Thu May 24 2018 - 09:19:56 BST
