Atmospheric State Focus Area

Limitations in specifying the state of the atmosphere (water vapor, temperature, clouds, and aerosols) are proving to be the largest hindrance for ARM in improving the radiative transfer codes.  Therefore, we need to use the best measurements ARM has in specifying the state of the atmosphere in order to position ourselves to improve the radiative codes.  The Atmospheric State geophysical focus area includes water vapor, temperature, pressure, and winds in the atmospheric column above the CART sites.  Clouds are covered in the Clouds focus area , while aerosols and trace gases are discussed in the Aerosols focus area . Here is a recognized need both within and outside the ARM community to improve the state-of-the-art in measuring the water vapor in the vertical column, both range-resolved and column-integrated.  The primary incentive inside the ARM Program has come from the recent recognition that attempts by the ARM Instantaneous Radiative Flux (IRF) group to quantify improvements to clear sky radiative transfer are currently limited by the uncertainty in the atmospheric water vapor distribution. A series of Water Vapor Intensive Operating Periods (WVIOPs) that have moisture characterization as their focus will be conducted to address this issue.  The overall goal of these IOPs is to develop techniques for obtaining the best possible water vapor measurements under a wide range of conditions (clear/cloudy, day/night, etc.) from a fusion of a variety of measurements.

Instruments that Measure Atmospheric State

Water Vapor

An unusually powerful array of tools for measuring water vapor at the SGP CART site is now complete and includes a microwave radiometer, Raman lidar, in-situ point measurements, and balloon borne soundings.

• BBSS - balloon borne sounding system at central and boundary facilities; radiosonde
• MWR - microwave radiometer at central and boundary facilities; integrated precipitable water vapor and liquid overhead
• RL at central facility; water vapor profiles in lower troposphere
• SMOS surface meteorological observing systems at extended facilities (including one at central facility); humidity at 2-m height
• THWAPS -- at the boundary facilities and central facility - humidity as a reference for radiosondes
• 60-m tower at central facility; humidity at heights of 60 m and 25 m

Temperature

• BBSS -- at central and boundary facilities - radiosondes
• IRT -- at central facility (with MWR) -- cloud base or sky temperature (downwelling)
• MFR(IRT) -- at central facility (with MFR platform on 10-m SIRS platform) - surface infrared temperature of pasture (upwelling)
• MFR(IRT) -- at central facility (with MFR platform at 25-m level of 60-m tower) - surface infrared temperature of wheat field (upwelling)
• RWP50 -- at central facility - acoustic virtual temperature profiles
• RWP915 -- at central facility and intermediate facilities - acoustic virtual temperature profiles
• SMOS -- at extended facilities (including one at central facility) air temperature at 2-m height
• SWATS -- at extended facilities (including one at central facility) - Soil temperature profiles
• THWAPS -- at the boundary facilities and central facility - surface temperature as a reference for radiosondes
• 60-m tower at central facility - air temperature at heights of 60 m and 25 m

Wind

• BBSS -- at central and boundary facilities - radiosondes
• ECORs -- on 60-m tower at central facility - wind speed and direction at heights of 60 m and 25 m
• RWP50 -- at central facility - profiles of mean horizontal wind speed and direction
• RWP915 -- at central facility and intermediate facilities - profiles of mean horizontal wind speed and direction
• SMOS -- at extended facilities (including one at central facility) - wind speed and direction at height of 10 m
• THWAPS -- at the boundary facilities and central facility - surface wind speed and direction as a reference for radiosondes

Atmospheric State Measurements

Specific Pressure
Pressure, atmospheric, at altitude
Pressure, atmospheric, at or near surface
Pressure, vapor, at or near surface

Temperature
Temperature, HBB, flag indicating stability
Temperature, absolute, retrieved profile
Temperature, air, ambient, at or near surface
Temperature, air, at 1.5 m
Temperature, air, at 9 m
Temperature, air, at or near surface
Temperature, air, at or near surface, statistics
Temperature, atmospheric mean radiating, MWR IPM output using sonde T,P,RH
Temperature, blackbody, ambient blackbody
Temperature, blackbody, cold blackbody
Temperature, blackbody, hot blackbody
Temperature, brightness, 23.8 GHz sky, MWR IPM output using sonde T,P,RH
Temperature, brightness, 31.4 GHz sky, MWR IPM output using sonde T,P,RH
Temperature, brightness, at shortwave and longwave wavenumbers
Temperature, brightness, longwave elevated air from radiance average (700_705 cm-1)
Temperature, brightness, longwave scene spectral averages (AERI Ch1)
Temperature, brightness, longwave surface air from radiance average (675_680 cm-1)
Temperature, brightness, shortwave elevated air from radiance average (2282_2287 cm-1)
Temperature, brightness, shortwave scene spectral averages (AERI Ch2)
Temperature, brightness, shortwave surface air from radiance average (2295_2300 cm-1)
Temperature, dew point, retrieved profile
Temperature, dewpoint, at altitude
Temperature, dry bulb, at altitude
Temperature, instrument
Temperature, soil, at 10 cm, maximum
Temperature, soil, at 10 cm, minimum
Temperature, soil, at 5 cm, maximum
Temperature, soil, at 5 cm, minimum
Temperature, soil, at various depths beneath natural sod cover
Temperature, soil, beneath bare soil
Temperature, soil, {at various depths}

Wind
Wind component, at altitude, S-to-N, calculated
Wind component, at altitude, W-to-E, calculated
Wind component, at altitude, eastward
Wind component, at altitude, northward
Wind direction, at 10 m, vector average
Wind direction, at altitude
Wind direction, at or near surface
Wind direction, at or near surface, resultant
Wind direction, at or near surface, standard deviation
Wind direction, at or near surface, standard deviation of
Wind magnitude, at or near surface, vector average
Wind run, at or near surface, average (arithmetic average speed)
Wind speed, at 2 m, average
Wind speed, at altitude
Wind speed, at or near surface
Wind speed, at or near surface, maximum (fastest minute)
Wind speed, at or near surface, maximum 3-second within 5-min averaging period
Wind speed, at or near surface, mean
Wind speed, at or near surface, resultant
Wind speed, at or near surface, standard deviation
Wind speed, at or near surface, vector averaged
Wind status, at altitude