Several GCMD Requests

[GES DISC - ingridgs]

1. POLAR VORTEX
Science Keywords>EARTH SCIENCE>ATMOSPHERE>WEATHER EVENTS > POLAR VORTEX
DESCRIPTION:
The stratospheric polar vortex is a large-scale region of air that is contained by a strong west-to-east jet stream that circles the polar region. This jet stream is usually referred to as the polar night jet. The polar vortex extends from the tropopause (the dividing line between the stratosphere and troposphere) through the stratosphere and into the mesosphere (above 50 km). Low values of ozone and cold temperatures are associated with the air inside the vortex.
REFERENCE:
https://ozonewatch.gsfc.nasa.gov/facts/vortex_NH.html

2. POLARIZATION
Science Keywords> EARTH SCIENCE> SPECTRAL/ENGINEERING> POLARIZATION
DESCRIPTION:
The polarization of an electromagnetic wave is the direction of the wave’s oscillating electric field.
Light is considered polarized if the component electromagnetic waves all share the same polarization, i.e., if the electric fields all oscillate in the same direction.
REFERENCE:
https://www.mit.edu/~ashrstnv/polarization.html

3. THERMAPAUSE
Locations > VERTICAL LOCATION > THERMAPAUSE
DESCRIPTION:
The thermopause is the atmospheric boundary of Earth's energy system, located at the top of the thermosphere. The temperature of the thermopause could range from nearly absolute zero to 987.547 °C (1,810 °F).
REFERENCE:
https://www.noaa.gov/jetstream/atmosphere/layers-of-atmosphere

4. TROPOPAUSE
Locations > VERTICAL LOCATION > TROPOPAUSE
DESCRIPTION:
The tropopause is the atmospheric boundary that demarcates the lowest two layers of the atmosphere of Earth – the troposphere and stratosphere – which occurs approximately 17 kilometres (11 mi) above the equatorial regions, and approximately 9 kilometres (5.6 mi) above the polar regions.

REFERENCE:
https://www.noaa.gov/jetstream/atmosphere/layers-of-atmosphere

5. TROPOPAUSE HEIGHT
This keyword already exists, but it is not well defined.
It exists here: Science Keywords>EARTH SCIENCE>ATMOSPHERE>ALTITUDE>TROPOPAUSE
but it should be: Science Keywords>EARTH SCIENCE>ATMOSPHERE>ALTITUDE>TROPOPAUSE HEIGHT
TROPOPAUSE is a vertical location in the atmosphere, but when nested under altitude, it should be obious that it is defining its height.
If GCMD is not diferientiating between the vertical location and the altitude, then I suggest to be all homogenious and only use the vertical location, and therefore, remove it from the keyword nested under altitude.

6. Aerosol Backscattering Ratio
Science Keywords>EARTH SCIENCE>ATMOSPHERE>AEROSOLS> Aerosol Back Scattering Ratio
DESCRIPTION:
It is a measure of the scattering in the backward direction ( i.e. towards the incident direction, at an scattering angle of 180 deg., sometimes also meant for scattering at an angle larger than 90 deg. ) for the light encountering the atmospheric aerosol particles.

REFERENCE:
https://airbornescience.nasa.gov/category/meas/Aerosol_Backscattering

7. Diffraction Grating
Science Keywords>EARTH SCIENCE>SPECTRAL/ENGINEERING> Diffraction Grating
DESCRIPTION:
Surface with parallel grooves or slits that enable diffraction of incoming light into optical spectra.

REFERENCE:
https://www.thorlabs.com/diffraction-gratings-tutorial?tabName=Gratings%20Tutorial

[GCMD - tstevens]

Thank you for your keyword request. We will review them and let you know when it is complete.

[GCMD - tstevens]

@GES DISC - ingridgs

Can you provide a new reference URL for POLAR VORTEX? The one you have listed has a broken link.

TROPOPAUSE HEIGHT
There are 177 collections that already use this keyword, so we want to consider the impacts of this change first. You can see the list of collections at https://search.earthdata.nasa.gov/search?q=TROPOPAUSE&ac=true&fs10=Tropopause&fsm0=Altitude&fst0=Atmosphere. Have you considered nesting TROPOPAUSE HEIGHT under TROPOPAUSE? That might be a good structure to help organize the boundary layer and the specific measurement. There are other boundary keywords under ALTITUDE, so you want to consider a consistent structure.

Aerosol Backscattering Ratio
Did you consider if Aerosol Backscattering Ratio should be nested under AEROSOL BACKSCATTER or at the same level of the hierarchy? AEROSOL BACKSCATTER is defined as the redirection of electromagnetic radiation due to the interaction with molecules or particles.

[GES DISC - ingridgs]

@GCMD - tstevens

The link for Polar Vortex works fine for me, is not broken. Also, is the only one I found that comes from NASA.

TROPOPAUSE HEIGHT: You can decide how to organize it.
I am just stating, that as of now it is NOT consistent.

• Why is currently Tropopause listed under ALTITUDE (Science Keywords>EARTH SCIENCE>ATMOSPHERE ALTITUDE>TROPOPAUSE), but "Boundry Layer", "exosphere", "ionosphere", "troposphere", etc are listed under VERTICAL LOCATION?

Yes, Aerosol Backscattering Ratio makes sense to be nested under AEROSOL BACKSCATTER

[GCMD - tstevens]

@GES DISC - ingridgs

Thank you for the additional information. I can make those changes. I would suggest that for 'TROPOPAUSE HEIGHT'; we pause on that keyword change and review it with the rest of the team first if you are ok with that. We may want to consider a broader update to keywords within 'ALTITUDE' and their consistency with 'VERTICAL LOCATION'.