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2004: Calibration of multi-satellite observations for climatic studies: Microwave sounding unit (MSU
- J. Geophys. Res
"... [1] The Microwave Sounding Units (MSU) aboard the NOAA series of polar orbiting satellites has been used by three groups to monitor the very small trend in the global tropospheric temperature over the 25-year satellite record. To obtain a homogeneous data set, each group made different calibration c ..."
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[1] The Microwave Sounding Units (MSU) aboard the NOAA series of polar orbiting satellites has been used by three groups to monitor the very small trend in the global tropospheric temperature over the 25-year satellite record. To obtain a homogeneous data set, each group made different calibration corrections of the MSUs in the form of fixed biases, and in some cases temperature-dependent adjustments, to each of the nine satellite instruments using data during the overlap periods. Up until now, however, the adjustments are empirically based. To improve the accuracy as well as our understanding of the error sources, this paper develops an alternate, physical approach for intercalibrating the MSU instruments. The paper develops a calibration model for the MSU instrument that includes the errors in the cold space and warm target measurements, as well as the nonlinear factor. Corrections for these calibration errors are estimated using a least squares minimization where the predictors are the differences between all 12 overlapping satellite measurements at low and high latitudes. After applying the calibration corrections, the zonally averaged differences between satellite instruments are no larger than 0.03 K, independent of latitude. It is also found that the tropospheric temperature trend derived
Stratospheric influence on MSUderived tropospheric temperature trends: a direct error analysis
- J Clim
"... Retrievals of tropospheric temperature trends from data of the Microwave Sounding Unit (MSU) are subject to biases related to the strong cooling of the stratosphere during the past few decades. The magnitude of this stratospheric contamination in various retrievals is estimated using a vertical prof ..."
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Retrievals of tropospheric temperature trends from data of the Microwave Sounding Unit (MSU) are subject to biases related to the strong cooling of the stratosphere during the past few decades. The magnitude of this stratospheric contamination in various retrievals is estimated using a vertical profile of stratospheric temperature trends based on observations. It is found that from 1979 to 2001 the stratospheric contribution to the trend of MSU channel 2 brightness temperature is about –0.08 K/decade, which is consistent with the findings of Fu et al. (2004). In the retrieval method developed by Fu et al. based on a linear combination of MSU channels 2 and 4, the stratospheric influence is largely removed, leaving a residual influence of about –0.01 K/decade. In contrast, the trend-error in the angular-scanning retrieval of lower tropospheric temperature from Christy et al. (2003) is about-0.03 to-0.04 K/decade.
2005. Determination of an Amazon Hot Reference Target for the On-Orbit Calibration of Microwave Radiometers
"... A physically based model is developed to determine hot calibration reference brightness temperatures (TBs) over depolarized regions in the Amazon rain forest. The model can be used to evaluate the end-to-end calibration of any satellite microwave radiometer operating at a frequency between 18 and 40 ..."
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A physically based model is developed to determine hot calibration reference brightness temperatures (TBs) over depolarized regions in the Amazon rain forest. The model can be used to evaluate the end-to-end calibration of any satellite microwave radiometer operating at a frequency between 18 and 40 GHz and angle of incidence between nadir and 55°. The model is constrained by Special Sensor Microwave Imager (SSM/I) TBs measured at 19.35, 22.2, and 37.0 GHz at a 53 ° angle of incidence and extrapolates/interpolates those measurements to other frequencies and incidence angles. The rms uncertainty in the physically based model is estimated to be 0.57 K. For instances in which coincident SSM/I measurements are not available, an empirical formula has been fit to the physical model to provide hot reference brightness temperature as a function of frequency, incidence angle, time of day, and day of year. The empirical formula has a 0.1-K rms deviation from the physically based model for annual averaged measurements and at most a 0.6-K deviation from the model for any specific time of day or day of year. 1.
Observation and Interpretation of Microwave Cloud Signatures over the Arctic Ocean during Winter
, 2001
"... An analysis of satellite microwave brightness temperatures at 85 GHz (37 GHz) shows that these temperatures sometimes vary by more than 30 K (15 K) within 1 or 2 days at a single location over Arctic sea ice. This variation can be seen in horizontal brightness temperature distributions with spatial ..."
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An analysis of satellite microwave brightness temperatures at 85 GHz (37 GHz) shows that these temperatures sometimes vary by more than 30 K (15 K) within 1 or 2 days at a single location over Arctic sea ice. This variation can be seen in horizontal brightness temperature distributions with spatial scales of hundreds of kilometers, as well as in brightness temperature time series observed at a single location. Analysis of satellite observations during winter shows that such brightness temperature warming frequently occurs in the Arctic Ocean, particularly in regions over which low pressure systems often pass. By comparing the observed microwave brightness temperature warming with ground-based measurements of geophysical variables collected during the Surface Heat Budget of the Arctic (SHEBA) experiment and with numerical prediction model analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF), it is found that brightness temperature anomalies are significantly correlated with clouds and precipitation. This finding raises the possibility of using satellite microwave data to estimate cloud liquid water path and precipitation in the Arctic. Factors contributing to the brightness temperature warming were examined, and it was found that the primary contributors to the observed warming were cloud liquid water and surface temperature change. 1.
2002: Potential for estimating cloud liquid water path over sea ice from airborne passive microwave measurements
- J. Geophys. Res
"... airborne passive microwave measurements ..."
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4. TITLE AND SUBTITLE GLOBAL EVALUATION OF SPECIAL SENSOR MCRO WAVE/MAGER OCEAN SURFACE WIND SPEED RETRIEVAL ALGORITHMS FOR THE PERIOD SEPTMEBER 1991-APRIL1992
, 1995
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CORRECTING FOR PRECIPITATION EFFECTS IN SATELLITE-BASED PASSIVE MICROWAVE TROPICAL CYCLONE INTENSITY ESTIMATES
, 2005
"... Public reporting burden for this collection of Information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments ..."
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Public reporting burden for this collection of Information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this
CORRECTING FOR PRECIPITATION EFFECTS IN SATELLITE-BASED PASSIVE MICROWAVE TROPICAL CYCLONE INTENSITY ESTIMATES
, 2005
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THE DESIGN AND DEVELOPMENT OF A GEOSTATIONARY SYNTHETIC THINNED APERTURE RADIOMETER
, 2009
"... 2008 For my parents Who for reasons unbeknownst to me Love me unconditionally ii Table of Contents Dedication.......................................................................................................................... ii ..."
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2008 For my parents Who for reasons unbeknownst to me Love me unconditionally ii Table of Contents Dedication.......................................................................................................................... ii
© Author(s) 2006. This work is licensed under a Creative Commons License. Atmospheric Chemistry and Physics Imaging gravity waves in lower stratospheric AMSU-A radiances, Part 1: Simple forward model
, 2006
"... Abstract. Using a simplified model of in-orbit radiance acquisition by the Advanced Microwave Sounding Unit (AMSU-A), we derive three-dimensional temperature weighting functions for Channel 9 measurements (peaking at ∼60–90 hPa) at all 30 cross-track beam positions and use them to investigate the se ..."
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Abstract. Using a simplified model of in-orbit radiance acquisition by the Advanced Microwave Sounding Unit (AMSU-A), we derive three-dimensional temperature weighting functions for Channel 9 measurements (peaking at ∼60–90 hPa) at all 30 cross-track beam positions and use them to investigate the sensitivity of these radiances to gravity waves. The vertical widths of the weighting functions limit detection to waves with vertical wavelengths of �10 km, with slightly better vertical wavelength sensitivity at the outermost scan angles due to the limb effect. Fourier Transforms of two-dimensional cross-track weighting functions reveal optimal sensitivity to cross-track wavelengths at the near-nadir scan angles, where horizontal measurement footprints are smallest. This sensitivity is greater for the AMSU-A on the Aqua satellite than for the identical instruments
