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Daniel J. Cecil and Edward J. Zipser

1. Introduction Understanding, estimating, and predicting such parameters as rainfall, vertical motion, and latent heating in precipitation systems requires some understanding of the microphysical characteristics of clouds and precipitation. Hurricanes provide an excellent environment for studying precipitation processes ( Marks et al. 1998 ), as the precipitation field is long lived and generally well organized by the flow of the vortex. Black and Hallett (1986, 1999) utilize observations

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Erin E. Jones, Kevin Garrett, and Sid-Ahmed Boukabara

( Andersson et al. 2007 ; Geer et al. 2014 ). In this study, we focus on the assimilation of humidity observations from the Sondeur Atmosphérique du Profil d’Humidité Intertropicale par Radiométrie (SAPHIR) on board the Megha-Tropiques satellite, which measures radiances across six channels in the 183-GHz band and allows for the retrieval of atmospheric water vapor profiles over a greater vertical range of the atmospheric column compared to other microwave humidity sounders. Efforts to directly

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Rosanne Polkinghorne, Tomislava Vukicevic, and K. Franklin Evans

S. K. Dhall , 2006 : Dynamic Data Assimilation—A Least Squares Approach . Cambridge University Press, 654 pp . Liljegren , J. C. , 1994 : Two-channel microwave radiometer for observations of total column precipitable water vapor and cloud liquid water path. Preprints, Fifth Symp. on Global Change Studies, Nashville, TN, Amer. Meteor. Soc., 262

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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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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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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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