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Robert F. Adler
and
Edward B. Rodgers

times. This would result in a similar increase inthe LHR inside the circle. For the present case, the LHRinside the 1- latitude circle also r. ose, by a factor >2,between 3 and 5 October observations. These relationships indicate a possible application of microwave datain helping to determine the intensity and intensitychanges of tropical cyclones. 'The LHR within 4- latitude can be thought of asbeing proportional to the product of the area coveredby precipitation and the mean precipitation

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Masahiro Kazumori
,
Quanhua Liu
,
Russ Treadon
, and
John C. Derber

the calculated brightness temperatures with observations indicated that the new emissivity model performs better at low frequencies. A clear reduction of the wind-dependent bias was seen in the AMSR-E 10.65-GHz horizontally polarized channel. The sensitivity study showed that FASTEM-1 and the new emissivity model had a similar sensitivity to the sea surface temperature in the 6.925–89-GHz microwave frequencies. However, the new model had a much weaker sensitivity to surface wind speeds than FASTEM

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G. David Alexander
,
James A. Weinman
, and
J. L. Schols

represented by using a double sine series. Hoffman and Grassoti showed that their method had significant impacts on European Centre for Medium-Range Weather Forecasts (ECMWF) analyses, and significantly reduced the variance of the difference between the analysis and microwave sensor observations of IWV. Although one of our goals here—to match forecast fields to remotely sensed observations—is the same, we employ the method of digital image warping [e.g., Pratt (1991) ], sometimes referred to as rubber

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Frédéric Chevallier
and
Peter Bauer

earth radiation budget observations from satellites (e.g., Cess et al. 1997 ) but which only provide information relevant to bulk nonprecipitating cloud parameters. Precipitation analyses, however, require the simulation of microwave radiative transfer in the model atmosphere to be compared to available satellite data. Here, the availability of a sophisticated global operational model with simulation scales of the same order as satellite observations provides a unique tool to evaluate the model

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Xin Li
,
Xiaolei Zou
,
Mingjian Zeng
,
Ning Wang
, and
Fei Tang

assimilates conventional observations and clear-sky radiances from the Advanced Microwave Sounding Unit-A (AMSU-A), the High Resolution Infrared Radiation Sounder (HIRS-4), and the ATMS using the EnVar method. For HIRS-4 infrared radiances assimilation, the GSI default minimum residual method ( Eyre and Menzel 1989 ; Li et al. 2020 ) is applied for cloud detection that discriminates clear channels based on the derived cloud top pressure. For AMSU-A and ATMS assimilation, the existing GSI quality control

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G. David Alexander
,
James A. Weinman
,
V. Mohan Karyampudi
,
William S. Olson
, and
A. C. L. Lee

of the intensity and precipitation patterns associated with extratropical cyclones (e.g., Manobianco et al. 1994 ; Jones and Macpherson 1997 ). It is challenging, however, particularly over data-sparse regions, to obtain continuous and accurate estimates of instantaneous rain rate. Here, we describe a technique through which data from a variety of sources—passive microwave sensors, infrared sensors, and lightning flash observations—along with a classic image processing technique (digital image

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Stanley Q. Kidder
and
Kae Shyu

forecast errors are still unacceptablylarge. A primary difficulty is that tropical cyclones and their environments are poorly observed by conventionaldata networks. Satellite sounders, however, routinely provide numerous observations near these storms. Meanlayer temperatures from the Scanning Microwave Spectrometer (SCAMS) on board the Nimbus-6 satelliteare decomposed using empirical orthogonal functions, and the expansion coefficients are related to deviationsfrom persistence track forecasts. Based on

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P. Chambon
,
J.-F. Mahfouf
,
O. Audouin
,
C. Birman
,
N. Fourrié
,
C. Loo
,
M. Martet
,
P. Moll
,
C. Payan
,
V. Pourret
, and
D. Raspaud

Atmospheric Infrared Sounder (AIRS)], the observing system is dominated by their radiances, which represent 80% of the total observations ( Fig. 1 ). With 18 radiometers, microwave radiances reach a fractional amount of 10%. Other spaceborne instruments represent less than 3% [GNSS-RO, atmospheric motion vectors (AMVs), scatterometer winds], whereas the percentage of in situ conventional data (aircraft, sondes, surface stations) is only 7%. To avoid spatial observation error correlations, most satellite

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Clive E. Dorman
and
Robert H. Bourke

observations taken by ships and relating them to a given amount of precipitation, new estimates of oceanic rainfall for the Pacific Ocean between 30-S and 60-N have been derived.Satellite microwave measurements and Taylor's (1973) island analysis support our findings. Annualand quarterly rainfall maps. drawn from our estimates, agree with other modern, land-derivedvalues, but provide greater detail. Between the equator and 60~N, the annual depth and volume rainfall totals are 1282 mm and 1.16 x 10~ kma

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Zhiquan Liu
,
Craig S. Schwartz
,
Chris Snyder
, and
So-Young Ha

assimilating rain-affected microwave radiances, and the QC procedure prohibits the use of AMSU-A data in the precipitating TC core area. Thus, the improved track forecasts by assimilating AMSU-A radiances are likely due to a better depiction of large-scale environmental flow in the analyses and subsequent forecasts. To test this hypothesis, we verified the forecasts against GPS dropwindsonde observations released from NOAA G-IV aircraft ( Aberson 2010 ). The G-IV dropwindsondes sample the atmosphere below

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