Title
Water Vapor Continuum Absorption in the Microwave
Abstract
The accurate modeling of continuum absorption is crucial for the so-called window regions of the spectrum, the relatively transparent regions between lines. The window regions in the microwave are of critical importance for Earth remote sensing and data assimilation. Presented in this paper is an evaluation of the widely used Mlawer, Tobin, Clough, Kneizys, and Davis (MT_CKD) water vapor continuum model in the microwave region, performed using measurements from ground-based radiometers operated by the Department of Energy's Atmospheric Radiation Measurement Program at sites in Oklahoma, USA, and the Black Forest, Germany. The radiometers used were the Radiometrics 23.8/31.4-GHz microwave radiometers (MWRs), the Radiometer Physics GmbH 90/150-GHz MWR at high frequencies (MWRHF), and the Radiometrics 183 GHz G-band vapor radiometer profiler (GVRP). Radiometer measurements were compared with brightness temperatures calculated using radiosonde temperature and humidity profiles input to the monochromatic radiative transfer model (MonoRTM), which uses the MT_CKD continuum model. Measurements at 23.8 GHz were used to correct for biases in the total precipitable water vapor (PWV) from the radiosondes. The long-term 31.4 GHz data set, with a range of PWV values spanning from 0.15 to 5 cm, allowed the separation of uncertainties in the self- and foreign-broadened components of the water vapor continuum. The MT_CKD model has been updated in the microwave region to provide improved agreement with the measurements. MonoRTM has been updated accordingly. The results for the different instruments and frequencies were consistent, providing high confidence in the continuum updates. The estimated uncertainties on the updated continuum coefficients in MT_CKD are 4% on the foreign-broadened water vapor continuum and 4% on the self-broadened water vapor continuum.
Year
DOI
Venue
2011
10.1109/TGRS.2010.2091416
Geoscience and Remote Sensing, IEEE Transactions
Keywords
Field
DocType
atmospheric humidity,atmospheric precipitation,atmospheric techniques,microwave spectra,radiative transfer,radiometry,remote sensing,water,Atmospheric Radiation Measurement Program,Black Forest,Earth remote sensing,G-band vapor radiometer profiler,GVRP,Germany,H2O,MT-CKD water vapor continuum model,Mlawer-Tobin-Clough-Kneizys-Davis water vapor continuum model,MonoRTM,Oklahoma,USA,brightness temperature,continuum absorption,data assimilation,foreign broadened components,frequency 150 GHz,frequency 183 GHz,frequency 23.8 GHz,frequency 31.4 GHz,frequency 90 GHz,ground based radiometers,high frequency microwave radiometers,microwave window regions,monochromatic radiative transfer model,radiosonde humidity profiles,radiosonde temperature profiles,self broadened components,spectral window regions,total precipitable water vapor,water vapor continuum microwave absorption,Microwave propagation,microwave radiometry,passive microwave remote sensing
Microwave,Radiosonde,Brightness temperature,Remote sensing,Atmospheric radiative transfer codes,Atmospheric model,Atmospheric sciences,Radiative transfer,Mathematics,Water vapor,Radiometer
Journal
Volume
Issue
ISSN
49
6
0196-2892
Citations 
PageRank 
References 
5
1.29
8
Authors
4
Name
Order
Citations
PageRank
Vivienne H. Payne1264.38
Eli J. Mlawer2205.92
Karen E. Cady-Pereira35912.12
Jean-Luc Moncet4173.94