25 results on '"Yamamoto, Munehisa K."'
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2. Further Improvement of the Heavy Orographic Rainfall Retrievals in the GSMaP Algorithm for Microwave Radiometers
- Author
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Yamamoto, Munehisa K., Shige, Shoichi, Yu, Cheng-Ku, and Cheng, Lin-Wen
- Published
- 2017
3. Spatial Contrast of Geographically Induced Rainfall Observed by TRMM PR
- Author
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Hirose, Masafumi, Takayabu, Yukari N., Hamada, Atsushi, Shige, Shoichi, and Yamamoto, Munehisa K.
- Published
- 2017
4. Impact of Long-Term Observation on the Sampling Characteristics of TRMM PR Precipitation
- Author
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Hirose, Masafumi, Takayabu, Yukari N., Hamada, Atsushi, Shige, Shoichi, and Yamamoto, Munehisa K.
- Published
- 2017
5. Improvement of High-Resolution Satellite Rainfall Product for Typhoon Morakot (2009) over Taiwan
- Author
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Taniguchi, Aina, Shige, Shoichi, Yamamoto, Munehisa K., Mega, Tomoaki, Kida, Satoshi, Kubota, Takuji, Kachi, Misako, Ushio, Tomoo, and Aonashi, Kazumasa
- Published
- 2013
6. Typical Patterns of Microwave Signatures and Vertical Profiles of Precipitation in the Midlatitudes from TRMM Data
- Author
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Yamamoto, Munehisa K. and Nakamura, Kenji
- Published
- 2011
7. Comparison of Diurnal Variations in Precipitation Systems Observed by TRMM PR, TMI, and VIRS
- Author
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Yamamoto, Munehisa K., Furuzawa, Fumie A., Higuchi, Atsushi, and Nakamura, Kenji
- Published
- 2008
8. Implementation of a Rainfall Normalization Module for GSMaP Microwave Imagers and Sounders.
- Author
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Yamamoto, Munehisa K. and Kubota, Takuji
- Subjects
- *
MICROWAVES , *CUMULATIVE distribution function - Abstract
This paper introduces the Method of Microwave Rainfall Normalization (MMN) for the Global Satellite Mapping of Precipitation (GSMaP) algorithm in its latest version (V05, algorithm version 8), released in December 2021. The method aims to mitigate the discrepancy of GSMaP rainfall estimates among passive microwave (PMW) imagers/sounders (MWIs/MWSs) due to differences in sensor specifications and retrieval algorithms. The basic idea of the MMN module is to calibrate target PMW sensors with reference sensors (the Global Precipitation Measurement (GPM) Microwave Imager (GMI) and the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI)) using the cumulative distribution function (CDF) of the rain rate. Differences between the CDF and normalization table for MWSs are greater than MWIs due to different rain retrieval algorithms. More (less) MWS rainfall is detected over the ocean (land) than GMI rainfall. Matchup rainfall data between GMI and a target PMW sensor are compared to evaluate MMN performance. The monthly mean rainfall and mean bias error were improved for almost all PMW sensors. This study leaves open the possibility for further inter-calibration and improvement of rain detection and heavy rainfall retrievals. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. NOTES AND CORRESPONDENCE An Approach to Reliability Characterization of GSMaP Near-Real-Time Precipitation Product.
- Author
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Moeka YAMAJI, Takuji KUBOTA, and YAMAMOTO, Munehisa K.
- Subjects
SEASONS ,KALMAN filtering ,ALGORITHMS ,MICROWAVES ,OCEAN ,SNOW cover - Abstract
Reliability information of satellite precipitation products is required for various applications. This study describes and evaluates a reliability flag of the Global Satellite Mapping of Precipitation Near-Real-Time precipitation product (GSMaP_NRT). This flag was developed to characterize the reliability of GSMaP_NRT data simply and qualitatively by considering its algorithm characteristics. The reliability at each pixel is represented by any one of ten levels (10 being the best and 1 the worst) by considering three major factors: 1) "surface type reliability"--which takes into account that estimation of rainfall using passive microwave sensors is better over the oceans than over land and coastal areas; 2) "low-temperature reliability"--which takes into account the lower reliability due to surface snow cover in low-temperature conditions; and 3) "Moving Vector with Kalman Filter (MVK) propagation reliability"--which means that the reliability gets worse with the increase in time since the last overpass of the passive microwave sensor. To evaluate the utility of the reliability flag, statistical indices are calculated for each reliability level using gauge-calibrated ground radar data around Japan. It is found that the reliability flag represents the differences in GSMaP accuracy: the accuracy worsens as the reliability decreases. The GSMaP errors exhibit seasonal changes that are well represented by the ten levels of the reliability flag, indicating that the reliability flag can be used to catch seasonal variations in GSMaP accuracy due to changes in environmental factors. This study also raises the possibility of improving the reliability flag by using information related to heavy orographic rainfall. It is shown how the error features of heavy orographic rainfall differ from those of the total rainfall, and it is suggested that heavy orographic rainfall information can be utilized to further improve the reliability flag. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
10. CEReS Archived Satellites Related Datasets and These Applications
- Author
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HIGUCHI, Atsushi, TAKENAKA, Hideaki, HIROSE, Hiroshi, YAMAMOTO, Munehisa K., KOTSUKI, Shunji, IRIE, Hitoshi, TANAKA, Kenji, and HAYASAKI, Masamitsu
- Published
- 2014
11. Spatial contrast of Asian dust concentration between windward and leeward of mountains in Japan during 1-2 April 2007
- Author
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HAYASAKI, Masamitsu, YAMAMOTO, Munehisa K., HIGUCHI, Atsushi, SHIMIZU, Atsushi, MORI, Ikuko, and NISHIKAWA, Masataka
- Abstract
[ABSTRACT]During massive Asian dust episode for 1-2 April 2007, mass concentration of suspended particulate matter (SPM) rapidly began to increase in the morning on 1 April from coastal side of the Japan Sea. For the daytime 1 April, while rapid SPM increase and extreme high concentrations observed in Hokuriku and Tohoku, SPM concentrations in Kanto remained low level and increased from late afternoon. Ground lidar observation and rawinsonde sounding in Hokuriku show that the top height of dust layer (~ 2 km) approximately correspond to the base of temperature inversion. In Kanto, SPM increase began from east coast and then it advanced westward after 15 LT with easterly wind. The CloudSat/CPR and CALIPSO/CALIOP observations show that clouds over mainland Japan and the Japan Sea was found in the upper-level (> 6 km). Continuous meteorological observations show that cloud condensation and rainfall was not observed over mountains for the daytime 1 April. These results suggest that the temporal delaying of SPM increase in Kanto was caused by an indirect dust transport.
- Published
- 2010
12. A statistical analysis for the characteristics of cloud/precipitation system from Cloudsat data
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YAMAMOTO, Munehisa K., HIGUCHI, Atsushi, and HAYASAKI, Masamitsu
- Subjects
Physics::Atmospheric and Oceanic Physics ,Astrophysics::Galaxy Astrophysics - Abstract
[ABSTRACT]Global distributions of cloud largely effect earth radiation budgets. The heating / cooling effect differs depending on a type of cloud due to the differences of the characteristics of radiative process. Thus, it is important to understand cloud distributions classified into some cloud types. A cloud type classification method has been developed using multiple bands in visible and infrared using geostationary satellite. However, it was hard to classify the cloud types because of limit of information from optical thickness and cloud top height. In 2006, Cloudsat satellite carrying the Cloud Profiling Radar (CPR) was launched, and its observation enables us to find vertical distributions of cloud globally. This study tried to characterize cloud / precipitation characteristics and classify cloud types from vertical distributions of clouds observed by Cloudsat CPR. This study applied a base of vertical-method of the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) 2A23 algorithm to the vertical distributions of reflectivity factor (Z) from CPR in order to detect the bright band height (BBH) and cloud types. The detected BBH exists under 250-500 m from freezing height derived from a re-analysis data. The cloud types were classified into convective with large Z, stratiform with BBH, and others. In this presentation, we will also report the characteristics of global cloud distributions with / without precipitation, with shallow or anvil, and so on.
- Published
- 2010
13. Estimation of radiation budget using geostationary satellites
- Author
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TAKENAKA, Hideaki, YAMAMOTO, Munehisa K., HAYASAKI, Masamitu, HIGUCHI, Atsushi, SAITOH, Naoko, KUZE, Hiroaki, NISHIO, Fumihiko, TAKAMURA, Tamio, FUKUDA, Satoru, NAKAJIMA, Teruyuki, OKUYAMA, Arata, KOSAKA, Yuki, NAKAYAMA, Ryuichiro, OWADA, Hiromi, DATE, Kenji, and ONO, Tomoaki
- Abstract
[ABSTRACT]SW radiation budget is estimated using geostationary satellites (GMS-5, GOES-8, GOES-10, METOSAT-5, METEOSAT-7). Each satellite data are calibrated, and optics properties of the cloud are retrieved. An accurate calibrated data propose the better accuracy for analysis of cloud and radiation budget. In this study, cloud and SW radiation budget analysis are done by CAPCOM algorithm and EXAM SYSTEM. On the other hand, aerosol optical thickness is retrieved by L-REAP algorithm. We discuss the possibility of aerosol-cloud-radiation interaction in north Pacific ocean and north Atlantic ocean.
- Published
- 2010
14. Diurnal variation of cloudiness over South Asia using satellite observations
- Author
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BHATT, B. C., KOH, T.-Y., YAMAMOTO, Munehisa K., and NAKAMURA, K.
- Abstract
[ABSTRACT]The climatological features of the diurnal cycle of cloudiness were investigated over three convective centers of interest over South Asia: over the Himalayas; north India and the Bay of Bengal (BOB). Three hourly blackbody brightness temperature (TBB) data from the METEOSAT-5 and rainfall data (3B42) from the Tropical Rainfall Measuring Mission (TRMM) were utilized. Analysis was concentrated on pre-monsoon and the summer monsoon season. Two methods were used to detect cloudiness: one method counted cloud clusters (CC) and utilized cloud tracking technique to identify time clusters (TC); and the other method computed cloud cover frequency (CCF). CC was defined as a contiguous area of pixels with TBB lower than the threshold of 219 K. The CCF was derived using 235 K as the threshold. From the analysis, it was noted that there were many CC over north India in the pre-monsoon season especially during the late afternoon hours. But deep convective activity was weaker over the region during the summer monsoon season. Bimodal diurnal cycle in CC occurrence was noted over the Himalayas during the summer monsoon season. It was noted that the peak convective activity occurred at 6 LT for the Bay of Bengal during both the summer monsoon and the pre-monsoon season. The life cycle of cloud clusters during summer monsoon season was also investigated. The diurnal cycle varied with location. There appeared a gradual delay in the preferred time of initiation, attainment of maximum area and dissipation as one progresses northward from BOB region through north India to the Himalayas.
- Published
- 2010
15. Estimation of Radiation budget using Geostationary Satellites Formation of a virtual laboratory for diagnosing the Earth's climate system
- Author
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TAKENAKA, Hideaki, YAMAMOTO, Munehisa K., HAYASAKI, Masamitsu, HIGUCHI, Atsushi, NISHIO, Fumihiko, KUZE, Hiroaki, TAKAMURA, Tamio, OKUYAMA, Arata, KOSAKA, Yuki, NAKAYAMA, Ryuichiro, OWADA, Hiromi, DATE, Kenji, and ONO, Tomoaki
- Abstract
[ABSTRACT]In this study, we develop a vicarious calibration technique and estimation algorithm of radiation budget for the global analysis. The vicarious calibration technique using three components ( clear sky sea surface, clear sky land surface, uniform cloud top) is applied to the geostationary satellites. This vicarious calibration technique is based on radiative transfer calculations and it has each optical properties (aerosol, cloud, surface BRDF/albedo) in three compon_~ntsT. he quality of three geostationary satellites (GMS-5, GOES-10, GOES-8) visible channel fixed accurately for global analysis. An accurate calibrated data set propose the better accuracy for analysis of cloud and radiation budget. Thus, cloud and radiation budget analysis algorithm are applied to new calibrated data set for global analysis. This is first result of trial for global analysis.
- Published
- 2009
16. Structures of Explosively Developing Extratropical Cyclones in Northwestern Pacific by Satellite Data
- Author
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YAMAMOTO, Munehisa K., HAYASAKI, Masamitsu, and HIGUCHI, Atsushi
- Abstract
[ABSTRACT]Horizontal distributions of explosively developing extratropical cyclone formed and developed in Northwestern Pacific Ocean in precipitation, water vapor, cloud liquid water, and surface wind fields are analyzed using the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on Aqua Satellite dataset in recent 7 winter seasons. Cyclone center-relative compositing mean fields are constructed for four life stages: 1) developing, 2) maximum deepening, 3) minimum center sea level pressure (SLP), and 4) decaying. These stages are distinguished by a value and a kind of differentiation in center SLP using a database of cyclone tracking derived from a reanalysis dataset. The developing processes of the composited cyclone are documented. In developing stage, the・ water vapor pass (WVP) has south-north (high-low) contrast corresponding to the temperature distribution. Corresponding to the cold-dry air mass advections, WVP concentration starts from western part of the cyclone center in the maximum deepening stage. The concentration is distinct along the cold front in the minimum SLP stage. The horizontal distributions at the maximum deepening stage agree with the previous study using global objectively analyzed dataset (GANAL). As the deepening rate is larger, the value and concentration is higher and stronger. Precipitation appears around_ the root of front corresponding to large cloud liquid water, while there is no precipitation near the cyclone center in minimum center SLP and decaying stages regardless of the strength.
- Published
- 2009
17. Characteristics of Backscattering Coefficients over Different Vegetation Land Covers Derived from TRMM/PR
- Author
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NAGAOKA, Junichi, YAMAMOTO, Munehisa K., and HIGUCHI, Atsushi
- Abstract
[ABSTRACT]The characteristics of backscattering coefficients ( cr0 ) observed by the Tropical Rainfall Measuring Mission (TRMM) / Precipitation Radar (PR) were investigated,for different vegetation covers; evergreen broadleaf forests ( ebf), woody savannas, savannas, open shrublands, and grasslands in Africa. For ebf, cr0 decreases rapidly from nadir to 3 °, then the rest of the angles are constant. On the other hand, cr0 gradually decreases from nadir to 17° for savannas, open shrublands, and grasslands. For woody savannas, cr0 value for each angle bin in the dry season is similar to that for savannas, but the characteristics of cr0 in the rainy season is similar to that for ebf. The maximum monthly mean precipitation corresponds to that of cr0 at nadir and 17° for grasslands and savannas. For grasslands, cr0 at 3 ° does not increase that is likely to be saturated from the dry season to the rainy season when Leaf Are Index (LAI) is more than 0.5. Seasonal variations of cr0 do not clearly correspond to that of precipitation for ebf where LAI is more than 3. It implies that cr0 at 3° is susceptible to vegetation canopy. It suggests that the combination of 3 ° and 17° of cr0 enable to classify vegetation land covers.
- Published
- 2009
18. Current Status and Future Perspective of CEReS Satellites Data Archive and Distribution
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HIGUCHI, Atsushi, YAMAMOTO, Munehisa K., HAYASAKI, Masamitsu, TAKENAKA, Hideaki, KITAYAMA, Tomoaki, AOKI, Saeko, CHIBA, Mayumi, KUZE, Hiroaki, KONDOH, Akihiko, JOSAPHAT, Tetuko Sri Sumantyo, and NISHIO, Fumihiko
- Abstract
[ABSTRACT]Primary function of Center for Environmental Remote Sensing (CEReS) is to provide satellite dataset such as GMS, MTSAT-IR, and NOAA/AVHRR for research community. We started data archive system (DAS) re-construction since 2005. New DAS based on PC servers and RAID storages with Free Operi Source Software (FOSS). Such configuration changes allow us to easy-expansion of DAS and random data access via 1intemet, thus downloaded files by users have been increased since 2005. In addition, activities of Virtual Laboratory (VL) for diagnosing the climate system accelerate the volume of archived satellite data since 2007. Our primary task in VL is collection and utilizations of geostationary meteorological satellites, thus we re-process raw full-disk data into grided format (after geometric correction) and open through the internet. Such data processing is not only contributed to VL also related communities. We will play an important role as one of data active archive center (DAAC) in Asia for satellite and related dataset.
- Published
- 2009
19. Heavy Ice Precipitation Band in an Oceanic Extratropical Cyclone Observed by GPM/DPR: 1. A Case Study.
- Author
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Akiyama, Shizuka, Shige, Shoichi, Yamamoto, Munehisa K., and Iguchi, Toshio
- Subjects
ICE ,METEOROLOGICAL precipitation ,OCEAN ,CYCLONES ,METEOROLOGICAL precipitation measurement - Abstract
Heavy ice precipitation (HIP) flags in the products of dual‐frequency precipitation radar (DPR) on board the Global Precipitation Measurement (GPM) core satellite indicate the existence of large ice particles. In this study, we analyzed the distribution of a HIP band detected along the warm front of an oceanic extratropical cyclone. The HIP band was more than 125 km long and probably exceeded the 245‐km range of the Ku‐band precipitation radar. We found two zones with distinct microphysical processes in the HIP band. Ice particles near the echo top height showed little change in their median size with height, where frontogenetical updraft was maximum. This suggests that particles are generated and grown in this zone by the updrafts. In the zone below, the particle sizes increased as the height decreased, implying particles aggregate as they fall. Plain Language Summary: Bands of heavy snowfall are often reported in the presence of extratropical cyclones over land. However, observations of bands of heavy snowfall over the ocean are limited. In this study, we detected a band of heavy snowfall occurring over the ocean using satellite‐borne precipitation radar for the first time. This signal had a narrow width of 10–20 km and a length that was likely greater than the 245‐km swath of the Ku‐band radar. We examined the change in precipitation echoes with height for the snowfall to understand how ice particles grow and subsequently result in heavy snowfall. The analysis suggested that in the upper layer of the heavy snowfall band, ice particles are produced and grown by an upward flow, and that in the middle layer, they collide with other ice crystals, resulting in larger crystals, which subsequently fall. Further statistical analysis of similar signals could reveal the structure and driving mechanisms for heavy snowfall over the land and ocean in future studies. Key Points: We detected a heavy ice precipitation (HIP) band along the warm front of an oceanic cyclone observed by GPM/DPRIce particles are grown by updraft near the echo top height of the HIP band and then aggregate in the zone below [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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20. Vertical gradient of stratiform radar reflectivity below the bright band from the Tropics to the extratropical latitudes seen by GPM.
- Author
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Kobayashi, Kazuki, Shige, Shoichi, and Yamamoto, Munehisa K.
- Subjects
RADAR meteorology ,REFLECTANCE measurement ,METEOROLOGICAL precipitation ,STRATUS clouds ,TROPICAL meteorology - Abstract
This study examined the vertical gradient of radar reflectivity below the detected bright band in stratiform regions from the Tropics to the extratropical latitudes using data from the Ku‐band (13.6 GHz) precipitation radar on board the Global Precipitation Measurement (GPM) Core Observatory. Stratiform precipitation profiles with reflectivity decreasing (increasing) from the melting level toward the surface occur frequently in the tropical oceans (mid‐ and high‐latitude oceans). High fractions of downward increasing stratiform pixels are found over the North Pacific Ocean throughout the year and over East Asia except for winter. In contrast, the North American continent and the adjacent North Atlantic Ocean are characterized by low fractions of downward‐increasing pixels during summer. The difference is consistent with the dominant type of convection over East Asia (warm‐type clouds) and over the North American continent (cold‐type clouds). Even in the tropical oceans such as the Atlantic and eastern Pacific intertropical convergence zones, there are some areas with moderate fractions of downward‐increasing stratiform pixels where the warm rain process dominates. The downward reduction of reflectivity in the stratiform region of MCSs is obviously due to evaporation, which is a function of lower‐tropospheric relative humidity. The downward increase of reflectivity in stratiform regions over the midlatitude oceans appears the result of raindrop growth. This is achieved via the collection of cloud droplets while falling through low‐level clouds produced by large‐scale vertical motion in the lower troposphere due to large‐scale convergence associated with synoptic‐scale systems. This study examined the vertical structure of radar reflectivity below the detected bright band in stratiform regions using data from the Ku‐band precipitation radar on board the Global Precipitation Measurement (GPM) Core Observatory. Reflectivity decreases toward the surface in the stratiform region of mesoscale convection [(a) and (c)], indicating a downward reduction of rainwater content. In stratiform regions of synoptic‐scale weather systems, such as extratropical cyclones [(b) and (d)], reflectivity increases toward the surface, indicating a downward increase of rainwater content. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
21. Development of GSMaP prototype in pre-TRMM era and satellite rainfall climate study
- Author
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YAMAMOTO, Munehisa K., SHIGE, Shoichi, and HIGUCHI, Atsushi
- Abstract
[ABSTRACT] A long-term accumulated observation data is expected to diagnose the climate study statistically. Although rain gauge data has been mainly utilized for rainfall climatology, satellite rainfall products combining data obtained by microwave radiometers (MWRs) in low Earth orbit and by infrared radiometers (IRs) such as the Global Precipitation Climatology Project (GPCP) are available since late 1970s. However, spatiotemporal resolution is rough (2.5 ° in latitude-longitude grid and 1 monthly) and the quality is not fully enough. Owing to sparse satellite MWR observations, rainfall is mainly estimated from IR. The great success of the Tropical Rainfall Measuring Mission (TRMM) accelerated development of the rain retrieval algorithm for MWR. High spatiotemporal resolution satellite rainfall products (0.1 °-0.25 ° in latitude-longitude grid and 0.5-3 hourly) have been available after the Tropical Rainfall Measuring Mission (TRMM) launch since 1998. The development of the rain retrieval algorithm combined MWRs and IR is enabling us to provide rainfall climatology using satellite rainfall data before the TRMM launch (-1998, pre-TRMM era). In this study, a prototype of GSMaP rainfall data in pre-TRMM era is constructed. Surface rainfall in 1987-1999 is estimated by the latest version of GSMaP MWR algorithms using the Special Sensor Microwave Imager (SSM/I) onboard Defencse Meteorological Satellite Program (DMSP) satellites F8, F10, F11, F12, F13, and F15. The Japanese-55-year Reanalysis data is used for atmospheric variables instead of the Global Analysis (GANAL). The 27 years of prototype GSMaP data may stand up to rainfall climate study. In this presentation, a time series and horizontal distributions of monthly-accumulated GSMaP rainfall will be compared with other satellite rainfall products. In pre-TRMM era, the geostationary meteorological satellite data is more important to estimate rainfall precisely because the MWRs observation is scarse.
- Published
- 2015
22. Improvement of the Rain/No-Rain Classification Method for Microwave Radiometers Over the Tibetan Plateau.
- Author
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Yamamoto, Munehisa K., Tanaka, Ippei, and Shige, Shoichi
- Abstract
This letter identifies causes of the deterioration of the Global Satellite Mapping of Precipitation rain detection over the Tibetan Plateau during the summer monsoon season. Using the rain/no-rain classification (RNC) method over the Plateau, observed brightness temperature (Tb) at 21 (23) GHz from the Tropical Rainfall Measuring Mission Microwave Imager (the Defense Meteorological Satellite Program Special Sensor Microwave Imager) [Tb(21 V) and Tb(23 V)], and surface emissivity ( $\varepsilon )$ was substituted for surface temperatures (Ts) to exclude areas of low Ts as snow cover because it is difficult to distinguish between the scattering signals of precipitation and snow cover. A case study demonstrates that rain systems are excluded because Ts is often below the threshold for snow cover due to the use of an inadequate value for $\varepsilon $ (constant value throughout the year), even though a rain scattering signal at high-frequency channels under no snow cover is evident. After $\varepsilon $ is replaced with values from a monthly mean satellite observation-based land surface emissivity database, rainfall detection is improved. In addition, it is suggested that a database of RNCs should also consider diurnal variations in Tb(21 V) and Tb(23 V) due to large diurnal differences over the Plateau. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
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23. Impact of Long-Term Observation on the Sampling Characteristics of TRMM PR Precipitation.
- Author
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MASAFUMI HIROSE, TAKAYA, YUKARI N., ATSUSHI HAMADA, SHOICHI SHIGE, and YAMAMOTO, MUNEHISA K.
- Subjects
METEOROLOGICAL precipitation ,RAINFALL ,CLIMATOLOGY ,PRECIPITATION anomalies - Abstract
Observations of the Tropical Rainfall Measuring Mission Precipitation Radar (TRMM PR) over 16 yr yielded hundreds of large precipitation systems (⩾100 km) for each 0.1° grid over major rainy regions. More than 90% of the rainfall was attributed to large systems over certain midlatitude regions such as La Plata basin and the East China Sea. The accumulation of high-impact snapshots reduced the significant spatial fluctuation of the rain fraction arising from large systems and allowed the obtaining of sharp images of the geographic rainfall pattern. Widespread systems were undetected over low-rainfall areas such as regions off Peru. Conversely, infrequent large systems brought a significant percentage of rainfall over semiarid tropics such as the Sahel. This demonstrated an increased need for regional sampling of extreme phenomena. Differences in data collected over a period of 16 yr were used to examine sampling adequacy. The results indicated that more than 10% of the 0.1°-scale sampling error accounted for half of the TRMM domain even for a 10-yr data accumulation period. Rainfall at the 0.1° scale was negatively biased in the first few years for over more than half of the areas because of a lack of high-impact samples. The areal fraction of the 0.1°-scale climatology with a 50% accuracy exceeded 95% in the ninth year and in the fifth year for those areas with rainfall >2 mm day
-1 . A monotonic increase in the degree of similarity of finescale rainfall to the best estimate with an accuracy of 10% illustrated the need for further sampling. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
24. Implementation of an orographic/nonorographic rainfall classification scheme in the GSMaP algorithm for microwave radiometers.
- Author
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Yamamoto, Munehisa K. and Shige, Shoichi
- Subjects
- *
MOUNTAINS , *RAINFALL , *METEOROLOGICAL satellites , *METEOROLOGICAL precipitation , *MICROWAVE radiometers - Abstract
We incorporate an orographic/nonorographic rainfall classification scheme into the Global Satellite Mapping of Precipitation algorithm for passive microwave radiometers. It improves rainfall estimation over the entire Asian region. However, low verification scores over the United States and Mexico result because vertical profiles of rainfall over the Sierra Madre Mountains are high even for orographic rainfall conditions. In this region, lightning activity is vigorous, with large amounts of solid particles such as graupels, occurring with strong convections. Hence, the orographic/nonorographic rainfall classification scheme is switched off for regions where strong lightning activity occurs in the rainfall type database. The revised zonal mean rainfall amounts obtained from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager are now in better agreement with those from the version 7 of the TRMM Precipitation Radar over the United States and Mexico, as well as Asia. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
25. Vertical and horizontal structure of winter precipitation systems over the western Pacific around Japan using TRMM data.
- Author
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Yamamoto, Munehisa K., Higuchi, Atsushi, and Nakamura, Kenji
- Published
- 2006
- Full Text
- View/download PDF
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