Date: Mon, 21 May 2018 11:18:05 +0000
From: Martin Juckes - UKRI STFC <martin.juc...@stfc.ac.uk>
To: Karl Taylor <taylo...@llnl.gov>, Jonathan Gregory
<j.m.greg...@reading.ac.uk>, "cf-metadata@cgd.ucar.edu"
<cf-metadata@cgd.ucar.edu>
CC: "yves.balkan...@lsce.ipsl.fr" <yves.balkan...@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 <taylo...@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-boun...@cgd.ucar.edu><mailto:cf-metadata-boun...@cgd.ucar.edu> on behalf of
Jonathan Gregory <j.m.greg...@reading.ac.uk><mailto:j.m.greg...@reading.ac.uk>
Sent: 18 May 2018 13:31
To: cf-metadata@cgd.ucar.edu<mailto:cf-metadata@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 <taylo...@llnl.gov><mailto:taylo...@llnl.gov>
Sent: 17 May 2018 15:58
To: Juckes, Martin (STFC,RAL,RALSP); Pamment, Alison (STFC,RAL,RALSP);
cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>;
yves.balkan...@lsce.ipsl.fr<mailto:yves.balkan...@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_particles_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 literature 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_direct_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_direct_effect
(W m-2)
4.7
surface_net_downward_shortwave_flux_in_air_due_to_dust_ambient_aerosol_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@cgd.ucar.edu<mailto:cf-metadata@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.pamm...@stfc.ac.uk<mailto:alison.pamm...@stfc.ac.uk>
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
-----Original Message-----
From: CF-metadata
<cf-metadata-boun...@cgd.ucar.edu><mailto:cf-metadata-boun...@cgd.ucar.edu> On
Behalf Of Alison Pamment - UKRI STFC
Sent: 14 May 2018 08:47
To: Juckes, Martin (STFC,RAL,RALSP)
<martin.juc...@stfc.ac.uk><mailto:martin.juc...@stfc.ac.uk>;
cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>
Cc: Jean-Yves Peterschmitt
<jean-yves.peterschm...@lsce.ipsl.fr><mailto:jean-yves.peterschm...@lsce.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_biolo
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_biolo
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 process 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_pa
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_particle
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_par
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 the 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_particles
(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 hygroscopic
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_assumin
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_cl
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 relative 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 through 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 taken 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.pamm...@stfc.ac.uk<mailto:alison.pamm...@stfc.ac.uk>
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
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