scholarly journals Impact of Misrepresentation of Freezing-Level Height by the TRMM Algorithm on Shallow Rain Statistics over India and Adjoining Oceans

2013 ◽  
Vol 52 (9) ◽  
pp. 2001-2008 ◽  
Author(s):  
K. Saikranthi ◽  
T. Narayana Rao ◽  
B. Radhakrishna ◽  
S. Vijaya Bhaskara Rao
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Precipitation Radar ◽  
Study Region ◽  
Freezing Level ◽  
Northwestern India ◽  
Trmm Precipitation ◽  
Radar Measurements ◽  
The Impact ◽  
The Himalaya ◽  
Level Height

AbstractThe estimation of freezing level-height (FLH) by the Tropical Rainfall Measuring Mission (TRMM) algorithm is evaluated, against several other data sources, over India and adjoining oceans. It is observed that the TRMM algorithm either underestimates or overestimates the FLH [relative to radiosonde- and ECMWF Interim Re-Analysis (ERA)-derived FLH] at latitudes > 20°N over India. The agreement between the FLHs obtained from ERA and radiosonde and the TRMM-derived brightband height suggests that usage of ERA-derived FLH may improve shallow rain statistics. The impact of misrepresentation of FLH by the TRMM algorithm on shallow rain statistics is assessed by using 13 yr of TRMM precipitation radar measurements. It is noted that the misidentification of FLH alone affects (mostly underestimates) the shallow rain occurrence and rain fraction by 3%–8% over the study region. The magnitude of underestimation is large over the southern slopes of the Himalaya, the northern plains, and in northwestern India. TRMM identifies most of the shallow rain (30%–50%) as cold rain in regions where the underestimation of FLH is high. This situation could introduce some error in the correction of reflectivity for attenuation and in the retrieval of latent heat profiles.

“Warm Rain” in the Tropics: Seasonal and Regional Distributions Based on 9 yr of TRMM Data

2009 ◽  
Vol 22 (3) ◽  
pp. 767-779 ◽  
Author(s):  
Chuntao Liu ◽  
Edward J. Zipser
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Precipitation Radar ◽  
Near Surface ◽  
Freezing Level ◽  
Tropical Oceans ◽  
Warm Rain ◽  
Seasonal And Diurnal Variations ◽  
Radar Echo ◽  
Trmm Precipitation ◽  
The Tropics

Abstract How much precipitation is contributed by warm rain systems over the tropics? What is the typical size, intensity, and echo top of warm rain events observed by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar over different regions of the tropics? What proportion of warm raining areas is actually attached to the edges of cold systems? Are there mesoscale warm raining systems, and if so, where and when do they occur? To answer these questions, a 9-yr TRMM precipitation feature database is used in this study. First, warm rain features in 20°S–20°N are selected by specifying precipitation features 1) with minimum infrared brightness temperature > 0°C, 2) with TRMM Precipitation Radar (PR) echo top below freezing level, or 3) without any ice-scattering signature in the microwave observations, respectively. Then, the geographical, seasonal, and diurnal variations of the rain volume inside warm rain features defined in these three ways are presented. The characteristics of warm rain features are summarized. Raining pixels with cloud-top temperature above 0°C contribute 20% of the rainfall over tropical oceans and 7.5% over tropical land. However, about half of the warm pixels over oceans and two-thirds of the warm pixels over land are attached to cold precipitation systems. A large amount of warm rainfall occurs over oceans near windward coasts during winter. Most of the warm rain systems have small size < 100 km2 and weak radar echo with a modal maximum near-surface reflectivity around 23 dBZ. However, mesoscale warm rain systems with strong radar echoes do occur in large regions of the tropical oceans, more during the nighttime than during daytime. Though the mean height of the warm precipitation features over oceans is lower than that over land, there is no significant regional difference in its size and intensity.

Statistical and Physical Analysis of the Vertical Structure of Precipitation in the Mountainous West Region of the United States Using 11+ Years of Spaceborne Observations from TRMM Precipitation Radar

2013 ◽  
Vol 52 (2) ◽  
pp. 408-424 ◽  
Author(s):  
Qing Cao ◽  
Yang Hong ◽  
Jonathan J. Gourley ◽  
Youcun Qi ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Complex Terrain ◽  
Vertical Structure ◽  
Tropical Rainfall Measuring Mission ◽  
The United States ◽  
Physical Analysis ◽  
Precipitation Radar ◽  
Surface Precipitation ◽  
Freezing Level ◽  
Physically Based ◽  
Trmm Precipitation

AbstractThis study presents a statistical analysis of the vertical structure of precipitation measured by NASA–Japan Aerospace Exploration Agency’s (JAXA) Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) in the region of southern California, Arizona, and western New Mexico, where the ground-based Next-Generation Radar (NEXRAD) network finds difficulties in accurately measuring surface precipitation because of beam blockages by complex terrain. This study has applied TRMM PR version-7 products 2A23 and 2A25 from 1 January 2000 to 26 October 2011. The seasonal, spatial, intensity-related, and type-related variabilities are characterized for the PR vertical profile of reflectivity (VPR) as well as the heights of storm, freezing level, and bright band. The intensification and weakening of reflectivity at low levels in the VPR are studied through fitting physically based VPR slopes. Major findings include the following: precipitation type is the most significant factor determining the characteristics of VPRs, the shape of VPRs also influences the intensity of surface rainfall rates, the characteristics of VPRs have a seasonal dependence with strong similarities between the spring and autumn months, and the spatial variation of VPR characteristics suggests that the underlying terrain has an impact on the vertical structure. The comprehensive statistical and physical analysis strengthens the understanding of the vertical structure of precipitation and advocates for the approach of VPR correction to improve surface precipitation estimation in complex terrain.

scholarly journals Possible Misidentification of Rain Type by TRMM PR over Tibetan Plateau

2007 ◽  
Vol 46 (5) ◽  
pp. 667-672 ◽  
Author(s):  
Yunfei Fu ◽  
Guosheng Liu
Keyword(s):  
Tibetan Plateau ◽  
Common Knowledge ◽  
Tropical Rainfall Measuring Mission ◽  
Stratiform Rain ◽  
Freezing Level ◽  
Central Tibetan Plateau ◽  
Standard Product ◽  
Trmm Pr ◽  
Trmm Precipitation ◽  
Rain Events

Abstract Rain-type statistics derived from Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) standard product show that some 70% of raining pixels in the central Tibetan Plateau summer are stratiform—a clear contradiction to the common knowledge that rain events during summer in this region are mostly convective, as a result of the strong atmospheric convective instability resulting from surface heating. In examining the vertical distribution of the stratiform rain-rate profiles, it is suspected that the TRMM PR algorithm misidentifies weak convective rain events as stratiform rain events. The possible cause for this misidentification is believed to be that the freezing level is close to the surface over the plateau, so that the ground echo may be mistakenly identified as the melting level in the PR rain classification algorithm.

scholarly journals Characteristics of Summer Precipitation around the Western Ghats and the Myanmar West Coast

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Dibas Shrestha ◽  
Rashila Deshar ◽  
Kenji Nakamura
Keyword(s):  
West Coast ◽  
Western Ghats ◽  
Large Scale ◽  
Summer Precipitation ◽  
Tropical Rainfall Measuring Mission ◽  
Precipitation Radar ◽  
Maximum Rainfall ◽  
Trmm Precipitation ◽  
The Western Ghats ◽  
Coastal Mountain

Characteristics of summer (June–August) precipitation over two coastal mountain regions in South Asia (Western Ghats: WG and Myanmar West Coast: MWC) with a focus on topographic impact are analyzed using the 13-year (1998–2010) high spatial resolution (0.05° × 0.05°) version 6 data obtained from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). A relationship between precipitation patterns and topography was observed in the coastal mountains. In both the WG and MWC, maximum rainfall along a tight line on the upwind side of the coastal mountains is primarily attributed to rain frequency. However, intense precipitation was observed over the offshore regions. Compared with the WG, deeper and large-scale precipitation systems develop over the MWC, producing more intense rainfall. It is suggested that insufficient humidity deters large-scale convection over the WG, and the atmosphere is sufficiently moist over the MWC.

scholarly journals Karakteristik Ketinggian Melting Layer di Indonesia Berdasarkan Radar Hujan Yang Terpasang Di Satelit TRMM

2018 ◽  
Vol 10 (2) ◽  
pp. 73-82
Author(s):  
Rany Audia Dwianda ◽  
Marzuki Marzuki
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Sea Breezes ◽  
Tropical Rainfall ◽  
Melting Layer ◽  
Freezing Level ◽  
Trmm Pr ◽  
Total Data ◽  
Level Height

Ketinggian melting layer atau freezing level height (FH) di Indonesia telah diteliti melalui data radar hujan yang terpasang di satelit Tropical Rainfall Measuring Mission (TRMM). Data yang digunakan adalah data TRMM 2A25 versi 7 selama 2011-2013. Nilai FH dari TRMM dibandingkan dengan nilai yang direkomendasikan oleh model ITU-R P.839. FH di Indonesia memiliki variasi musiman dan diurnal yang signifikan. Rata-rata bulanan FH menunjukkan pola bimodal dengan dua puncak dan dua lembah, mirip dengan pola curah hujan dan temperatur permukaan air laut di Indonesia. Puncak FH teramati pada bulan-bulan basah (musim hujan) ketika temperatur permukaan air laut tinggi. Nilai FH mencapai puncaknya pada sore hari yaitu sekitar jam 18-19 waktu setempat. Adanya perbedaan pola FH antara darat dan laut yang menandakan adanya pengaruh sirkulasi darat-laut (land-sea breezes). Pada dini dan pagi hari, hujan dengan FH > 5 km tidak teramati di daratan tetapi pada siang dan sore hari jumlahnya meningkat, terutama di Sumatera, Kalimantan dan Papua. Nilai FH tertinggi yang teramati dalam penelitian ini adalah 5,55 km yang teramati pada 2013, dan nilai terendah adalah 4,40 km, yang teramati pada 2012. Sebagian besar hujan yaitu sekitar 82% dari total data, memiliki FH lebih rendah dari yang direkomendasikan oleh ITU-R P.839 (5 km). Dengan demikian, model ITU-R menakar FH lebih tinggi dari semestinya. Selain itu, asumsi nilai FH yang konstan (5 km) dalam model ITU-R juga tidak tepat karena nilai FH di Indonesia menunjukkan variasi diurnal dan musiman yang signifikan.Kata kunci : melting layer, Indonesia, TRMM-PR, ITU-R P.839, variasi diurnal, variasi musiman 

scholarly journals Relationships between Rain Characteristics and Environment. Part I: TRMM Precipitation Features and the Large-Scale Environment over the Tropical Pacific

2012 ◽  
Vol 140 (9) ◽  
pp. 2831-2840 ◽  
Author(s):  
Chie Yokoyama ◽  
Yukari N. Takayabu
Keyword(s):  
Large Scale ◽  
Tropical Rainfall Measuring Mission ◽  
Warm Pool ◽  
Intertropical Convergence Zone ◽  
The Other ◽  
Precipitation Radar ◽  
Trmm Precipitation ◽  
Highly Correlated ◽  
The Western Pacific ◽  
The Tropical Pacific

Abstract Differences in the characteristics of rain systems in the eastern Pacific (EP) intertropical convergence zone (ITCZ) and the western Pacific (WP) warm pool are quantitatively examined in relation to the large-scale environment. This study mainly uses precipitation feature (PF) data observed by the precipitation radar (PR) on board the Tropical Rainfall Measuring Mission (TRMM). The PFs are classified into four types according to their areas and maximum heights. Rain from tall unorganized systems and very tall organized systems tends to be dominant in high-SST regions such as the WP. On the other hand, the EP has more rain from congestus and organized systems with moderate heights than the WP. It is shown that shallow rain from congestus and moderately deep rain from organized systems are highly correlated with shallow (1000–925 hPa) convergence fields with coefficients of 0.75 and 0.66, respectively. These relationships between characteristics of rain systems and the large-scale environment are robust through all seasons.

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