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Xinxuan Zhang and Emmanouil N. Anagnostou

Abstract

The study evaluated a numerical weather model (WRF)-based satellite precipitation adjustment technique with 81 heavy precipitation events that occurred in three tropical mountainous regions (Colombia, Peru, and Taiwan). The technique was applied on two widely used near-real-time global satellite precipitation products—the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center morphing technique (CMORPH) and the Global Satellite Mapping of Precipitation project (GSMaP)—for each precipitation event. The WRF-adjusted satellite products along with the near-real-time and gauge-adjusted satellite products as well as the WRF simulation were evaluated by independent gauge networks at daily scale and event total scale. Results show that the near-real-time precipitation products exhibited severe underestimation relative to the gauge observations over the three tropical mountainous regions. The underestimation tended to be larger for higher rainfall accumulations. The WRF-based satellite adjustment provided considerable improvements to the near-real-time CMORPH and GSMaP products. Moreover, error metrics show that WRF-adjusted satellite products outperformed the gauge-adjusted counterparts for most of the events. The effectiveness of WRF-based satellite adjustment varied with events of different physical processes. Thus, the technique applied on satellite precipitation estimates of these events may exhibit inconsistencies in the bias correction.

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Xiang Ni, Chuntao Liu, Daniel J. Cecil, and Qinghong Zhang

water in temperatures from −10° to −30°C, it is reasonable to relate the surface hail with high radar reflectivity values at these temperatures. Here, we utilize temperatures of radar echo tops to develop thresholds to reduce the areal discrepancy, especially the discrepancy between the midlatitudes and tropics. The T_MAXHT values from 20 to 60 dB Z in 1-dB intervals are calculated by combining temperature profiles from the ERA-Interim reanalysis ( Dee et al. 2011 ) with the maximum reflectivity

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Sarah D. Bang and Daniel J. Cecil

across the globe, at least visually: well-known hail “hot spots” such as the central United States, northern Argentina, and the Bangladesh/eastern India region appear in each ( Cecil and Blankenship 2012 ; Ferraro et al. 2015 ; Ni et al. 2017 ; Mroz et al. 2017) . The most readily apparent differences, however, occur in the tropics, where different approaches represent hail to widely varying extents. In the climatologies of Mroz et al. (2017) and Ferraro et al. (2015) , and the passive

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Gail Skofronick-Jackson, Walter A. Petersen, Wesley Berg, Chris Kidd, Erich F. Stocker, Dalia B. Kirschbaum, Ramesh Kakar, Scott A. Braun, George J. Huffman, Toshio Iguchi, Pierre E. Kirstetter, Christian Kummerow, Robert Meneghini, Riko Oki, William S. Olson, Yukari N. Takayabu, Kinji Furukawa, and Thomas Wilheit

orbit allows the GPM CO to sample precipitation across all hours of the day from the tropics to the Arctic and Antarctic circles and for observing hurricanes and typhoons as they transition from the tropics to the midlatitudes. GPM expands TRMM’s reach not only in terms of global coverage, but also through sophisticated satellite instrumentation, the intercalibration of datasets from other microwave radiometers, coordinated merged precipitation datasets, reduced latency for delivering data

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Stephen E. Lang and Wei-Kuo Tao

. 2017 ). In the tropics, however, LH is typically the primary component for a wide range of tropical circulations beginning with the large-scale Hadley circulation where latent heat release within “hot towers” is the principal driver ( Riehl and Malkus 1958 ; Fierro et al. 2009 , 2012 ). LH can also lead to important feedbacks within monsoon circulations such as the East Asian summer monsoon ( Jin et al. 2013 ), the West African monsoon ( Hagos and Zhang 2010 ), and the South Asian monsoon

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Xiang Ni, Chuntao Liu, and Edward Zipser

1. Introduction Deep convection plays a crucial role in moisture and heat transfer in the tropics ( Riehl and Malkus 1958 ), and is a key component in organized convective systems ( Houze 1977 , 2004 ; Houze et al. 2015 ; Zipser 1977 ). They are commonly found in various kinds of weather systems, such as squall lines, hurricanes, and monsoons ( Xu and Zipser 2012 ; Jiang et al. 2011 ; Smull and Houze 1985 ). To quantify the role of the deep convection in latent heat release, it is

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Daniel J. Cecil and Themis Chronis

separately for each 5° latitude bin and for each month. Lower Θ values generally have better performance (i.e., less variation in PCT) in the deep tropics than at higher latitudes. At mid- and high latitudes, higher Θ values perform better during the warm season and lower Θ values perform better during the cold season. The Θ values that yield the highest percentage of land–water pairs with PCT differences less than 2 K are compiled as functions of latitude and month in Table 3 (89 GHz), Table 4 (37

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Toshio Iguchi, Nozomi Kawamoto, and Riko Oki

does not necessarily mean that solid precipitation reaches the surface. In fact, most ice precipitation detected in the tropics exists only at very high altitudes. To see whether the ice particles are reaching the actual surface in those cases, only the cases in which flagHeavyIcePrecip is set are counted and at the same time the surface air temperature is approximately below C. This temperature was estimated from the value stored in “phase” variable at the surface range bin determined by the KuPR

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W.-K. Tao, T. Iguchi, and S. Lang

precipitating, mostly warm rain cloud systems that are detectable using CloudSat ( Nelson et al. 2016 ; Nelson and L’Ecuyer 2018 ; Huaman and Schumacher 2018 ), the vast majority of rain and hence LH in the tropics comes from more intense rain associated with deeper convective clouds and convective cloud systems that were largely detectable ( Berg et al. 2010 ) by the Tropical Rainfall Measuring Mission (TRMM, launched in 1997) Precipitation Radar (PR). Therefore, LH has long been a standard product for

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Clément Guilloteau, Efi Foufoula-Georgiou, Christian D. Kummerow, and Veljko Petković

variable nature of convection in the tropics and subtropics: A legacy of 16 years of the Tropical Rainfall Measuring Mission satellite . Rev. Geophys. , 53 , 994 – 1021 , https://doi.org/10.1002/2015RG000488 . 10.1002/2015RG000488 Islam , T. , M. A. Rico-Ramirez , D. Han , P. K. Srivastava , and A. M. Ishak , 2012 : Performance evaluation of the TRMM precipitation estimation using ground-based radars from the GPM validation network . J. Atmos. Sol.-Terr. Phys. , 77 , 194 – 208

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