Aerosol variables and WMDR class modifications required to align with OSCAR requirements

[ejwelton]

Branch

https://github.com/wmo-im/wmds/blob/issue263/tables_en/1-01-01.csv

Summary and Purpose

Several aerosol variables must be redefined and renamed to align with OSCAR requirements, remove confusion about their nature, and allow for different observing methods to utilize the same variable. An additional variable from OSCAR requirements is missing in the code list and should be added. Next, the inclusion of wavelength and column or height information in the aerosol variable names and definitions should be removed. Instead, the new observedLayer code list should be used to specify if the variable is column or for specific layer(s). Also a wavelength class should be added to the WMDR schema and used to specify wavelength for variables that require it. Finally, if the decision to rename "aerosol" terms to "particle phase" is approved, then rename all aerosol terms used here to match.

Stakeholder(s)

WG ACV

Proposal

1. Variable: Light backscattering coefficient, total aerosol. This variable needs to be split into two separate variables to account for backscatter measurements at both 180 degrees and over the backwards hemisphere. These are fundamentally different variables and cannot share one name.

   1. Rename current variable to the following: Hemispheric Backscatter Coefficient, total aerosol. Definition: Incident radiative flux scattered into all backward angles, i.e. scattering_angle exceeding pi/2 radians, by total aerosol particles.
   2. Create new variable: Backscatter Coefficient, total aerosol. Definition: Incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   3. Create new variable: Hemispheric forward scattering coefficient. Definition: Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.

   Set status of variables 319, 320, 321 (Light backscattering coefficient) to "retired" and add new variables instead: notation	name	description
   new id	Particle light hemispheric backscatter coefficient	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians.
   new id	Particle light backscatter coefficient	The fraction of incident radiative flux scattered backward at 180 degrees.
   new id	Particle light hemispheric forward scattering coefficient	Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians.

2. Variable: Multi-wavelength optical depth, total aerosol. This does not match the OSCAR requirements, which do not demand multi-wavelength observations. In addition, optical depth measurements are made for individual wavelengths (with defined bandpass), and the current name is illogical as no optical depth value is "multi-wavelength". Suggest renaming this variable to "aerosol optical depth" to match the requirements table. Also suggest new definition to avoid specifying column observations (instead use the observedLayer code list). New Definition: The AOD is the effective depth of the aerosol over a specified distance, from the viewpoint of radiation propagation: Vertical integral of spectral aerosol extinction coefficient AOD = exp(-K. Δz) where K is the extinction coefficient [km-1 ] and Δz the vertical path [km].

   notation	name (old)	name (new)	description
   new id	Multi-wavelength optical depth, total aerosol	Aerosol optical depth, TSP	The AOD is the effective depth of the aerosol over a specified distance, from the viewpoint of radiation propagation: Vertical integral of spectral aerosol extinction coefficient AOD = exp(-K. Δz) where K is the extinction coefficient [km-1 ] and Δz the vertical path [km]

3. Variable: Vertical Distribution of Properties. This variable is meaningless and not in the OSCAR requirements. Set status of the following variable to "retired":	notation	name	description
   326	Vertical distribution of properties

4. Variables Particle Effective Sizes

   1. Aerosol Effective Radius. The current definition is not standard and is confusing since it includes conflicting references to both column and tropospheric observations. Use the observedLayer code list to separately specify whether the variable is column or layer(s). Suggest new definition: The area weighted mean radius of the aerosol particles.
   2. Create new variable "Aerosol Effective Diameter".

   notation	name (old)	name (new)	description (old)	description (new)
   362	Aerosol effective radius	Particle effective radius	3D field of mean aerosol particle size, defined as the ratio of the third and second moments of the number size distribution of aerosol particles. Requested in the troposphere (assumed height: 12 km) and as columnar average.	The area weighted mean radius of the aerosol particles.
   new id	-	Particle effective diameter	-	The area weighted mean diameter of the aerosol particles.

5. Add new variable to the Aerosol / Physical properties - primary subcategory. New variable: Aerosol Layer Height. This variable is in the OSCAR requirements already. The definition in the requirements table should be modified because it specifies an altitude range, and doing so for a variable that itself is a height is redundant and confusing. The current definition would also rule out using this variable for PBL and stratospheric aerosol layers. Use the observedLayer code list to separately specify atmospheric layer(s) if needed. Suggest new definition: Height of vertically localized aerosol layer above sea level.	notation	name	description	tags
   new id	Aerosol Layer Height	Height of vertically localized aerosol layer above sea level.	aerosol
   new id	Mixed layer height	Height above the surface to which atmospheric properties (wind speed, etc) or atmospheric constituents (aerosol, gases) are dispersed by turbulent vertical mixing	dynamics

Reason

Use of separate wavelength class and new observedLayer code list will remove confusion and conflicts with current names and definitions, and allow different instrument (observedMethods) to be matched with the same variable. This will reduce the need to add additional, similar sounding variables to the aerosol category. This proposal will also align the specified variables more accurately with the OSCAR requirements table.

---

original comment:

Branch https://github.com/wmo-im/wmds/blob/issue263/tables_en/1-01-01.csv

Summary and Purpose Several aerosol variables must be redefined and renamed to align with OSCAR requirements, remove confusion about their nature, and allow for different observing methods to utilize the same variable. An additional variable from OSCAR requirements is missing in the code list and should be added. Next, the inclusion of wavelength and column or height information in the aerosol variable names and definitions should be removed. Instead, the new observedLayer code list should be used to specify if the variable is column or for specific layer(s). Also a wavelength class should be added to the WMDR schema and used to specify wavelength for variables that require it. Finally, if the decision to rename "aerosol" terms to "particle phase" is approved, then rename all aerosol terms used here to match.

Stakeholder(s) WG ACV

Proposal

1. Utilize the new observedLayer code list to specify column or layer specific nature of the variable. The current practice of including this information in the name or definition should be stopped and variables renamed/defined accordingly. If not, this practice causes problems to use the same variable for instruments that measure column or profile data (in particular the definitions of some variables opposes use of the variable by profiling instruments).
2. Create a new wavelength class in the WMDR schema to use to describe the wavelength of aerosol variables from remote sensing observations. This could be a duplicate of the Frequency class but with definitions and units unique to wavelength. It is not feasible to ask optical remote sensing providers to utilize frequency. The community standard is wavelength. Furthermore, use of frequency would require an unrealistic degree of attention to significant figures in the reporting of the values.
3. Variable: Light backscattering coefficient, total aerosol. This variable needs to be split into two separate variables to account for backscatter measurements at both 180 degrees and over the backwards hemisphere. These are fundamentally different variables and cannot share one name. 3a. Rename current variable to the following: Hemispheric Backscatter Coefficient, total aerosol. Definition: The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles. 3b. Create new variable: Backscatter Coefficient, total aerosol. Definition: The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.
4. Variable: Multi-wavelength optical depth, total aerosol. This does not match the OSCAR requirements, which do not demand multi-wavelength observations. In addition, optical depth measurements are made for individual wavelengths (with defined bandpass), and the current name is illogical as no optical depth value is "multi-wavelength". Suggest renaming this variable to "aerosol optical depth" to match the requirements table. Also suggest new definition to avoid specifying column observations (instead use the observedLayer code list). New Definition: The AOD is the effective depth of the aerosol over a specified distance, from the viewpoint of radiation propagation: Vertical integral of spectral aerosol extinction coefficient AOD = exp(-K. Δz) where K is the extinction coefficient [km-1 ] and Δz the vertical path [km].
5. Variable: Vertical Distribution of Properties. This variable is meaningless and not in the OSCAR requirements. It should be deprecated.
6. Variable: Aerosol Effective Radius. The current definition is not standard and is confusing since it includes conflicting references to both column and tropospheric observations. Use the observedLayer code list to separately specify whether the variable is column or layer(s). Suggest new definition: The area weighted mean radius of the aerosol particles.
7. Add new variable to the Aerosol / Physical properties - primary subcategory. New variable: Aerosol Layer Height. This variable is in the OSCAR requirements already. The definition in the requirements table should be modified because it specifies an altitude range, and doing so for a variable that itself is a height is redundant and confusing. The current definition would also rule out using this variable for PBL and stratospheric aerosol layers. Use the observedLayer code list to separately specify atmospheric layer(s) if needed. Suggest new definition: Height of vertically localized aerosol layer above sea level.

Reason Use of separate wavelength class and new observedLayer code list will remove confusion and conflicts with current names and definitions, and allow different instrument (observedMethods) to be matched with the same variable. This will reduce the need to add additional, similar sounding variables to the aerosol category. This proposal will also align the specified variables more accurately with the OSCAR requirements table.

[fstuerzl]

1. see issue #268
2. see WMDR repository issue #43
3. in issue #280
4. see issue #280

5. Set status of the following variable to "retired":	notation	name	description
   326	Vertical distribution of properties

6. Change the name and definition of the variable "Aerosol effective radius":	notation	name (new)	description (old)	description (new)
   362	Particle effective radius	3D field of mean aerosol particle size, defined as the ratio of the third and second moments of the number size distribution of aerosol particles. Requested in the troposphere (assumed height: 12 km) and as columnar average.	The area weighted mean radius of the aerosol particles.

7. Add new variable:	notation	name	description	tags
   new id	Aerosol Layer Height	Height of vertically localized aerosol layer above sea level.	Physical properties

8. Set status of variables 319, 320, 321 (Light backscattering coefficient) to "retired" and add two new variables instead: notation	name	description
   new id	Hemispheric particle backscatter coefficient	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles.
   new id	Particle backscatter coefficient	The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.

9. Additions: notation	name	description
   new id	Particle light extinction coefficient
   new id	Particle single scattering albedo
   new id	Ångström exponent for particle light extinction
   new id	Ångström exponent for particle light scattering
   new id	Ångström exponent for particle light absorption
   new id	Ångström exponent for aerosol optical depth
   new id	Ångström exponent for aerosol absorption optical depth

   ---

   To do:

   • review proposals 5.-7.
   • confirm branch, view differences https://github.com/wmo-im/wmds/compare/issue263

[fstuerzl]

@gaochen-larc

Are we going to combine "Hygroscopic size growth factor", "Hygroscopic scattering growth factor", and "Hygroscopic extinction growth factor" to just one "Hygroscopic growth factor"?

Also, I would like to suggest to add "Surface Area Size Distribution", "Volume Density Size Distribution", "Mass Size Distribution". Comments? @markusfiebig and @charlesabrock

@charlesabrock:

Add new row to backscatter table: "Hemispheric forward scattering coefficient", defined as "Incident radiative flux scattered into all forward angles, ie scattering_angle from zero to pi/2 radians, by total aerosol particles."

Change backscattering entries from "The fraction of incident radiative flux. . ." to "Incident radiative flux. . . ."

@joergklausen

@markusfiebig Please description for

Hygroscopic particle size growth factor Hygroscopic particle light scattering growth factor Hygroscopic particle light extinction growth factor

[ejwelton]

Also add Angstrom exponents for aerosol optical depth: Ångström exponent for aerosol optical depth Ångström exponent for aerosol absorption optical depth

[markusfiebig]

Agreement to move "Aerosol effective radius" to "Particle effective radius".

[fstuerzl]

Updated proposal with only the following amendments to table 1-01-01:

---

Branch https://github.com/wmo-im/wmds/blob/issue263/tables_en/1-01-01.csv

Summary and Purpose Several aerosol variables must be redefined and renamed to align with OSCAR requirements, remove confusion about their nature, and allow for different observing methods to utilize the same variable. An additional variable from OSCAR requirements is missing in the code list and should be added. Next, the inclusion of wavelength and column or height information in the aerosol variable names and definitions should be removed. Instead, the new observedLayer code list should be used to specify if the variable is column or for specific layer(s). Also a wavelength class should be added to the WMDR schema and used to specify wavelength for variables that require it. Finally, if the decision to rename "aerosol" terms to "particle phase" is approved, then rename all aerosol terms used here to match.

Stakeholder(s) WG ACV

Proposal

1. Variable: Light backscattering coefficient, total aerosol. This variable needs to be split into two separate variables to account for backscatter measurements at both 180 degrees and over the backwards hemisphere. These are fundamentally different variables and cannot share one name.

   1. Rename current variable to the following: Hemispheric Backscatter Coefficient, total aerosol. Definition: Incident radiative flux scattered into all backward angles, i.e. scattering_angle exceeding pi/2 radians, by total aerosol particles.
   2. Create new variable: Backscatter Coefficient, total aerosol. Definition: Incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   3. Create new variable: Hemispheric forward scattering coefficient. Definition: Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.

   Set status of variables 319, 320, 321 (Light backscattering coefficient) to "retired" and add new variables instead: notation	name	description
   new id	Hemispheric particle light backscatter coefficient, TSP	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light backscatter coefficient, PM10	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light backscatter coefficient, PM1	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles.
   new id	Particle light backscatter coefficient, TSP	The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   new id	Particle light backscatter coefficient, PM10	The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   new id	Particle light backscatter coefficient, PM1	The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   new id	Hemispheric particle light forward scattering coefficient, TSP	Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light forward scattering coefficient, PM10	Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light forward scattering coefficient, PM1	Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.

   • Duplicate entries with size ranges PM1, PM10, TSP included for the time being, considering that the removal of size ranges from variable name will be postponed. This is only a temporary solution until the WMDR model is adapted.

2. Variable: Multi-wavelength optical depth, total aerosol. This does not match the OSCAR requirements, which do not demand multi-wavelength observations. In addition, optical depth measurements are made for individual wavelengths (with defined bandpass), and the current name is illogical as no optical depth value is "multi-wavelength". Suggest renaming this variable to "aerosol optical depth" to match the requirements table. Also suggest new definition to avoid specifying column observations (instead use the observedLayer code list). New Definition: The AOD is the effective depth of the aerosol over a specified distance, from the viewpoint of radiation propagation: Vertical integral of spectral aerosol extinction coefficient AOD = exp(-K. Δz) where K is the extinction coefficient [km-1 ] and Δz the vertical path [km].

   notation	name (old)	name (new)	description
   new id	Multi-wavelength optical depth, total aerosol	Aerosol optical depth, TSP	The AOD is the effective depth of the aerosol over a specified distance, from the viewpoint of radiation propagation: Vertical integral of spectral aerosol extinction coefficient AOD = exp(-K. Δz) where K is the extinction coefficient [km-1 ] and Δz the vertical path [km]

3. Variable: Vertical Distribution of Properties. This variable is meaningless and not in the OSCAR requirements. Set status of the following variable to "retired":	notation	name	description
   326	Vertical distribution of properties

4. Variables Particle Effective Sizes

   1. Aerosol Effective Radius. The current definition is not standard and is confusing since it includes conflicting references to both column and tropospheric observations. Use the observedLayer code list to separately specify whether the variable is column or layer(s). Suggest new definition: The area weighted mean radius of the aerosol particles.
   2. Create new variable "Aerosol Effective Diameter".

   notation	name (old)	name (new)	description (old)	description (new)
   362	Aerosol effective radius	Particle effective radius	3D field of mean aerosol particle size, defined as the ratio of the third and second moments of the number size distribution of aerosol particles. Requested in the troposphere (assumed height: 12 km) and as columnar average.	The area weighted mean radius of the aerosol particles.
   new id	-	Particle effective diameter	-	The area weighted mean diameter of the aerosol particles.

5. Add new variable to the Aerosol / Physical properties - primary subcategory. New variable: Aerosol Layer Height. This variable is in the OSCAR requirements already. The definition in the requirements table should be modified because it specifies an altitude range, and doing so for a variable that itself is a height is redundant and confusing. The current definition would also rule out using this variable for PBL and stratospheric aerosol layers. Use the observedLayer code list to separately specify atmospheric layer(s) if needed. Suggest new definition: Height of vertically localized aerosol layer above sea level.	notation	name	description	tags
   new id	Aerosol Layer Height	Height of vertically localized aerosol layer above sea level.	Physical properties

Reason Use of separate wavelength class and new observedLayer code list will remove confusion and conflicts with current names and definitions, and allow different instrument (observedMethods) to be matched with the same variable. This will reduce the need to add additional, similar sounding variables to the aerosol category. This proposal will also align the specified variables more accurately with the OSCAR requirements table.

[ejwelton]

I approve of the suggested changes in the new tables. Definition for the new particle effective diameter should match that for effective radius, just replace "radius" in the definition with "diameter". One note: here we've applied TSP to backscatter and aerosol optical depth, but its unclear if this has been done to extinction and Angstrom exponents in issue 289.

[fstuerzl]

Branch updated: https://github.com/wmo-im/wmds/compare/issue263

I approve of the suggested changes in the new tables. Definition for the new particle effective diameter should match that for effective radius, just replace "radius" in the definition with "diameter". One note: here we've applied TSP to backscatter and aerosol optical depth, but its unclear if this has been done to extinction and Angstrom exponents in issue 289.

-> description included in proposal above

[fstuerzl]

Since a more fundamentel reorganisation of the observed variable table was postponed (recommendation from WG ACV), the proposal is ready for validation.

Consolidated proposal:

Branch https://github.com/wmo-im/wmds/blob/issue263/tables_en/1-01-01.csv

Summary and Purpose Several aerosol variables must be redefined and renamed to align with OSCAR requirements, remove confusion about their nature, and allow for different observing methods to utilize the same variable. An additional variable from OSCAR requirements is missing in the code list and should be added. Next, the inclusion of wavelength and column or height information in the aerosol variable names and definitions should be removed. Instead, the new observedLayer code list should be used to specify if the variable is column or for specific layer(s). Also a wavelength class should be added to the WMDR schema and used to specify wavelength for variables that require it. Finally, if the decision to rename "aerosol" terms to "particle phase" is approved, then rename all aerosol terms used here to match.

Stakeholder(s) WG ACV

Proposal

1. Variable: Light backscattering coefficient, total aerosol. This variable needs to be split into two separate variables to account for backscatter measurements at both 180 degrees and over the backwards hemisphere. These are fundamentally different variables and cannot share one name.

   1. Rename current variable to the following: Hemispheric Backscatter Coefficient, total aerosol. Definition: Incident radiative flux scattered into all backward angles, i.e. scattering_angle exceeding pi/2 radians, by total aerosol particles.
   2. Create new variable: Backscatter Coefficient, total aerosol. Definition: Incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   3. Create new variable: Hemispheric forward scattering coefficient. Definition: Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.

   Set status of variables 319, 320, 321 (Light backscattering coefficient) to "retired" and add new variables instead: notation	name	description
   new id	Hemispheric particle light backscatter coefficient, TSP	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light backscatter coefficient, PM10	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light backscatter coefficient, PM1	The fraction of incident radiative flux scattered into all backward angles, ie scattering_angle exceeding pi/2 radians, by total aerosol particles.
   new id	Particle light backscatter coefficient, TSP	The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   new id	Particle light backscatter coefficient, PM10	The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   new id	Particle light backscatter coefficient, PM1	The fraction of incident radiative flux scattered backward at 180 degrees by total aerosol particles.
   new id	Hemispheric particle light forward scattering coefficient, TSP	Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light forward scattering coefficient, PM10	Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.
   new id	Hemispheric particle light forward scattering coefficient, PM1	Incident radiative flux scattered into all forward angles, i.e. scattering_angle from zero to pi/2 radians, by total aerosol particles.

   • Duplicate entries with size ranges PM1, PM10, TSP included for the time being, considering that the removal of size ranges from variable name will be postponed. This is only a temporary solution until the WMDR model is adapted.

2. Variable: Multi-wavelength optical depth, total aerosol. This does not match the OSCAR requirements, which do not demand multi-wavelength observations. In addition, optical depth measurements are made for individual wavelengths (with defined bandpass), and the current name is illogical as no optical depth value is "multi-wavelength". Suggest renaming this variable to "aerosol optical depth" to match the requirements table. Also suggest new definition to avoid specifying column observations (instead use the observedLayer code list). New Definition: The AOD is the effective depth of the aerosol over a specified distance, from the viewpoint of radiation propagation: Vertical integral of spectral aerosol extinction coefficient AOD = exp(-K. Δz) where K is the extinction coefficient [km-1 ] and Δz the vertical path [km].

   notation	name (old)	name (new)	description
   new id	Multi-wavelength optical depth, total aerosol	Aerosol optical depth, TSP	The AOD is the effective depth of the aerosol over a specified distance, from the viewpoint of radiation propagation: Vertical integral of spectral aerosol extinction coefficient AOD = exp(-K. Δz) where K is the extinction coefficient [km-1 ] and Δz the vertical path [km]

3. Variable: Vertical Distribution of Properties. This variable is meaningless and not in the OSCAR requirements. Set status of the following variable to "retired":	notation	name	description
   326	Vertical distribution of properties

4. Variables Particle Effective Sizes

   1. Aerosol Effective Radius. The current definition is not standard and is confusing since it includes conflicting references to both column and tropospheric observations. Use the observedLayer code list to separately specify whether the variable is column or layer(s). Suggest new definition: The area weighted mean radius of the aerosol particles.
   2. Create new variable "Aerosol Effective Diameter".

   notation	name (old)	name (new)	description (old)	description (new)
   362	Aerosol effective radius	Particle effective radius	3D field of mean aerosol particle size, defined as the ratio of the third and second moments of the number size distribution of aerosol particles. Requested in the troposphere (assumed height: 12 km) and as columnar average.	The area weighted mean radius of the aerosol particles.
   new id	-	Particle effective diameter	-	The area weighted mean diameter of the aerosol particles.

5. Add new variable to the Aerosol / Physical properties - primary subcategory. New variable: Aerosol Layer Height. This variable is in the OSCAR requirements already. The definition in the requirements table should be modified because it specifies an altitude range, and doing so for a variable that itself is a height is redundant and confusing. The current definition would also rule out using this variable for PBL and stratospheric aerosol layers. Use the observedLayer code list to separately specify atmospheric layer(s) if needed. Suggest new definition: Height of vertically localized aerosol layer above sea level.	notation	name	description	tags
   new id	Aerosol Layer Height	Height of vertically localized aerosol layer above sea level.	Physical properties

Reason Use of separate wavelength class and new observedLayer code list will remove confusion and conflicts with current names and definitions, and allow different instrument (observedMethods) to be matched with the same variable. This will reduce the need to add additional, similar sounding variables to the aerosol category. This proposal will also align the specified variables more accurately with the OSCAR requirements table.

[joergklausen]

Team agreed this as 'validated' pending editorial changes (drop size range)

[fstuerzl]

Team agreed this as 'validated' pending editorial changes (drop size range)

@joergklausen, editorial changes are done, the issue can be moved to "validated" on the project board.

[gaochen-larc]

The aerosol layer height is used as an indicator of vertical mixing and should not be tagged as aerosol physical properties. Comments?

[fstuerzl]

@gaochen-larc, I have changed the tag to "aerosol": https://github.com/wmo-im/wmds/commit/b7c84d077c74e4f521a4d2923b983f92a30bfd7e Do you agree with that?

[joergklausen]

@gaochen-larc I have just discussed this with @fstuerzl. I think there may be a misunderstanding between the two of you. Thus, the suggestion would be to tag this with "dynamics" and "particle phase" in lieu of aerosol physical properties. Does this respiond to your concerns, @gaochen-larc , or do I also get it wrong?

[gaochen-larc]

@gaochen-larc I have just discussed this with @fstuerzl. I think there may be a misunderstanding between the two of you. Thus, the suggestion would be to tag this with "dynamics" and "particle phase" in lieu of aerosol physical properties. Does this respiond to your concerns, @gaochen-larc , or do I also get it wrong?

I think "dynamics" is closer to what I meant. Sorry for the confusion. What are other available tags? I would say it is better to use "vertical mixing" or even "PBL". The relation with aerosol is that this height is determined by aerosol loading gradient...

[ejwelton]

I preferred the definition tagged to aerosol "Aerosol Layer Height,Height of vertically localized aerosol layer above sea level." This is closer to my original intention for this variable and the actual OSCAR variable definition (#357 in variable list). This is not to be confused with dynamical terms such as mixing or the PBL (they have separate definitions). In terms of PBL, one variable currently missing is the mixed layer height (or depth). This is related to PBL height (defined by thermodynamics), but is essentially the lowest aerosol layer that interacts with (or reaches) the surface. Mixed layer height is typically provided by lidar observations. Aerosol layer height is more generic and meant for any layer present in the vertical column.

[gaochen-larc]

I am convinced now. Thank you, @ejwelton, for clarification!

[joergklausen]

Sorry guys (@ejwelton @gaochen-larc), I am lost with your most recent comments. #357 in the variable list refers to UV Erythemally weighted ... please be clear with your comments, state specifically what you would like to be changed for "Aerosol layer height" and how (description, tags). For yet another new variable, "Mixed layer height", it is a bit late to enter the race, but if you're clear (name, description, tags), we can sneak it in. We need to resolve this by Wednesday, otherwise we'll not get it across the finish line.

[gaochen-larc]

I think @ejwelton and I agreed to change the tag to "aerosol" and no changes to description. Is this correct @ejwelton?

[fstuerzl]

@gaochen-larc, @ejwelton, @joergklausen, I included the tag "aerosol" in the final proposal above and in the branch.

[ejwelton]

@gaochen-larc @joergklausen Yes, for aerosol layer height change tag to "aerosol" and no changes to description. It appears I wrote the wrong ID for aerosol layer height in OSCAR variables, here is link: https://space.oscar.wmo.int/variables/view/aerosol_layer_height. It would be great to add "mixed layer height" if possible (I originally left this off the list because it is not in OSCAR requirements). Separate post on "mixed layer height" below.

[ejwelton]

Propose adding new variable with "dynamics" tag: mixed layer height. The mixed layer height is the height above the surface to which atmospheric properties (wind speed, etc) or atmospheric constituents (aerosol, gases) are dispersed by turbulent vertical mixing. The mixed layer height is the same as the PBL height for strong convective boundary layers, but not necessarily the same in all conditions (and their definitions are different). In practice, the mixed layer height is typically detected with ceilometer or lidar based on gradients in the aerosol backscatter profile. Thus it would be misleading for most ceilometer or lidar data providers to use the PBL height variable to describe what is in fact a mixed layer height. Only lidars capable of retrieving temperature or wind profiles can determine PBL height. Including mixed layer height variable would remove this problem.

[fstuerzl]

@ejwelton I'll include the following new variable in the branch and in the final proposal above:	notation	tags	name	description
new id	dynamics	Mixed layer height	Height above the surface to which atmospheric properties (wind speed, etc) or atmospheric constituents (aerosol, gases) are dispersed by turbulent vertical mixing

Please confirm!

[ejwelton]

confirm, thanks.

[joergklausen]

Proposal validated (including last minute addition of mixed layer height). Paths replaced with tags for new variables.

@amilan17 I would really be good to separate matrix from tags and structure tables 1-01-x accordingly with columns "notation", "matrix", "tags", "description"

[markusfiebig]

I possibly minor issue concerning the table above. I would use a slightly different order of terms within the property name, e.g. use "Particle light hemispheric backscatter coefficient", not "Hemispheric particle light backscatter coefficient", or I would use "Particle light hemispheric forward scattering coefficient", not "Hemispheric particle light forward scattering coefficient". With the changed syntax, the names would appear more systematic and easier to parse for a software if needed.

[gaochen-larc]

I agree with @markusfiebig and think "Particle light hemispheric forward scattering coefficient" is better. The word "hemispheric" is used to describe the scattering angles, related to the phase function. Similar changes should be made to "Hemispheric particle light backscatter coefficient"

[fstuerzl]

I possibly minor issue concerning the table above. I would use a slightly different order of terms within the property name, e.g. use "Particle light hemispheric backscatter coefficient", not "Hemispheric particle light backscatter coefficient", or I would use "Particle light hemispheric forward scattering coefficient", not "Hemispheric particle light forward scattering coefficient". With the changed syntax, the names would appear more systematic and easier to parse for a software if needed.

@amilan17, are we still in time to include this in the branch?

[ejwelton]

I agree to last changes proposed by @markusfiebig

[fstuerzl]

@markusfiebig, @gaochen-larc, @ejwelton thanks for your feedback. I see that it makes more sense this way. I've changed the proposal and the branch accordingly.

[gaochen-larc]

Thank you @fstuerzl !

[amilan17]

@joergklausen - do you confirm that this issue is valid and can go into FT2021-2? (I'm assuming yes, but it doesn't have the milestone nor your final approval)

[joergklausen]

Yes, I just verified (to the best of my abilities, anyway).

[gaochen-larc]

I confirm the validity of this branch