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 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.

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 

Morphology, Intensity, and Rainfall Production of MJO Convection: Observations from DYNAMO Shipborne Radar and TRMM

2015 ◽  
Vol 72 (2) ◽  
pp. 623-640 ◽  
Author(s):  
Weixin Xu ◽  
Steven A. Rutledge
Keyword(s):  
Mesoscale Convective System ◽  
Tropical Rainfall Measuring Mission ◽  
Radar Data ◽  
Convective System ◽  
Precipitation Radar ◽  
Convective Systems ◽  
Trmm Pr ◽  
Mesoscale Convective ◽  
Trmm Precipitation

Abstract This study uses Dynamics of the Madden–Julian Oscillation (DYNAMO) shipborne [Research Vessel (R/V) Roger Revelle] radar and Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) datasets to investigate MJO-associated convective systems in specific organizational modes [mesoscale convective system (MCS) versus sub-MCS and linear versus nonlinear]. The Revelle radar sampled many “climatological” aspects of MJO convection as indicated by comparison with the long-term TRMM PR statistics, including areal-mean rainfall (6–7 mm day−1), convective intensity, rainfall contributions from different morphologies, and their variations with MJO phase. Nonlinear sub-MCSs were present 70% of the time but contributed just around 20% of the total rainfall. In contrast, linear and nonlinear MCSs were present 10% of the time but contributed 20% and 50%, respectively. These distributions vary with MJO phase, with the largest sub-MCS rainfall fraction in suppressed phases (phases 5–7) and maximum MCS precipitation in active phases (phases 2 and 3). Similarly, convective–stratiform rainfall fractions also varied significantly with MJO phase, with the highest convective fractions (70%–80%) in suppressed phases and the largest stratiform fraction (40%–50%) in active phases. However, there are also discrepancies between the Revelle radar and TRMM PR. Revelle radar data indicated a mean convective rain fraction of 70% compared to 55% for TRMM PR. This difference is mainly due to the reduced resolution of the TRMM PR compared to the ship radar. There are also notable differences in the rainfall contributions as a function of convective intensity between the Revelle radar and TRMM PR. In addition, TRMM PR composites indicate linear MCS rainfall increases after MJO onset and produce similar rainfall contributions to nonlinear MCSs; however, the Revelle radar statistics show the clear dominance of nonlinear MCS rainfall.

“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.

scholarly journals A TRMM-Calibrated infrared technique for rainfall estimation: application on rain events over eastern Mediterranean

2006 ◽  
Vol 7 ◽  
pp. 181-188 ◽  
Author(s):  
H. Feidas ◽  
G. Kokolatos ◽  
A. Negri ◽  
M. Manyin ◽  
N. Chrysoulakis
Keyword(s):  
Eastern Mediterranean ◽  
Regional Scale ◽  
Tropical Rainfall Measuring Mission ◽  
Rain Gauge ◽  
Tropical Areas ◽  
Trmm Precipitation ◽  
Remote Sensing Techniques ◽  
Rain Events ◽  
Rain Rates ◽  
Rain Gauge Network

Abstract. The aim is to evaluate the use of a satellite infrared (IR) technique for estimating rainfall over the eastern Mediterranean. The Convective-Stratiform Technique (CST), calibrated by coincident, physically retrieved rain rates from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), is applied over the Eastern Mediterranean for four rain events during the six month period of October 2004 to March 2005. Estimates from this technique are verified over a rain gauge network for different time scales. Results show that PR observations can be applied to improve IR-based techniques significantly in the conditions of a regional scale area by selecting adequate calibration areas and periods. They reveal, however, the limitations of infrared remote sensing techniques, originally developed for tropical areas, when applied to precipitation retrievals in mid-latitudes.

scholarly journals Variations in Precipitating Convective Feature Populations with ITCZ Width in the Pacific Ocean

2020 ◽  
Vol 33 (10) ◽  
pp. 4391-4401 ◽  
Author(s):  
Kyle R. Wodzicki ◽  
Anita D. Rapp
Keyword(s):  
Pacific Ocean ◽  
Southern Oscillation ◽  
Walker Circulation ◽  
Tropical Rainfall Measuring Mission ◽  
Strong Positive Correlation ◽  
Stratiform Rain ◽  
The Pacific ◽  
Columnar Water Vapor ◽  
Trmm Precipitation ◽  
The Pacific Ocean

AbstractMany recent studies have aimed to better understand changes in the characteristics of the intertropical convergence zone (ITCZ), including ITCZ location, width, and precipitation intensity. However, very few studies have looked at the relationship between characteristics of convection within the ITCZ and ITCZ width. The present work uses information from an ITCZ identification database and Tropical Rainfall Measuring Mission (TRMM) precipitation feature (PF) database to quantify variations in convective characteristics across the ITCZ in the Pacific Ocean. Data are partitioned into wide and narrow ITCZ regimes to quantify differences in convection between different ITCZ regimes. Under the wide regime, convection deeper than 5 km, with areas greater than 100 km2, or stratiform rain fractions greater than 0.5 is, on average, 24%, 23%, and 12% more frequent, respectively. In the narrow regime, the signal is reversed, with average increases in the frequency of convection with heights below 5 km, areas less than 100 km2, or stratiform rain fractions less than 0.5 of 15%, 4%, and 6%, respectively. Positive and negative anomalies in columnar water vapor (CWV) and sea surface temperature (SST) across the ITCZ are observed in the wide and narrow regimes, respectively. There is also a strong positive correlation between an El Niño–Southern Oscillation (ENSO) index and ITCZ width anomalies, with wide (narrow) ITCZs occurring during warm (cold) phases of ENSO. This implies that the strengthening and weakening of the Walker circulation associated with ENSO may play a role in modulating the convective populations that contribute to the Pacific ITCZ width variations.

The Relative Importance of Stratiform and Convective Rainfall in Rapidly Intensifying Tropical Cyclones

2017 ◽  
Vol 145 (3) ◽  
pp. 795-809 ◽  
Author(s):  
Cheng Tao ◽  
Haiyan Jiang ◽  
Jonathan Zawislak
Keyword(s):  
Tropical Cyclones ◽  
Inner Core ◽  
Low Frequency ◽  
Tropical Rainfall Measuring Mission ◽  
Convective Precipitation ◽  
Relative Importance ◽  
Convective Rainfall ◽  
Stratiform Rain ◽  
Rainfall Frequency ◽  
Trmm Precipitation

Using 16-yr Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) observations, rainfall properties in the inner-core region of tropical cyclones (TCs) and the relative importance of stratiform and convective precipitation are examined with respect to the evolution of rapid intensification (RI) events. The onset of RI follows a significant increase in the occurrence and azimuthal coverage of stratiform rainfall in all shear-relative quadrants, especially upshear left. The importance of the increased stratiform occurrence in RI storms is further confirmed by the comparison of two groups of slowly intensifying (SI) storms with one group that underwent RI and the other that did not. Statistically, SI storms that do not undergo RI during their life cycle have a much lower percent occurrence of stratiform rain within the inner core. The relatively greater areal coverage of stratiform rain in RI cases appears to be related to the moistening/humidification of the inner core, particularly in the upshear quadrants. In contrast to rainfall frequency, rainfall intensity and total volumetric rain do not increase much until several hours after RI onset, which is more likely a response or positive feedback rather than the trigger of RI. Despite a low frequency of occurrence, the overall contribution to total volumetric rain by convective precipitation is comparable to that of stratiform rain, owing to its intense rain rate.

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 Geometric and Physical Characteristics of Precipitation Clouds in Tibetan Plateau

2022 ◽  
Vol 2022 ◽  
pp. 1-18
Author(s):  
Kunyu Teng ◽  
Hongke Cai ◽  
Xiubin Sun ◽  
Quanliang Chen
Keyword(s):  
Tibetan Plateau ◽  
Average Length ◽  
Vertical Direction ◽  
Tropical Rainfall Measuring Mission ◽  
Physical Characteristics ◽  
Convective Precipitation ◽  
The Tibetan Plateau ◽  
Average Rainfall ◽  
Trmm Precipitation ◽  
The Relationship

This paper examines the basic geometric and physical characteristics of precipitation clouds over the Tibetan Plateau, based on the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data from 1998 to 2015, using the minimum bounding rectangle (MBR) method. The results show that about 60% of the precipitation clouds occur with a scale of approximately 18 km (length) and 15 km (width), and the proportion of precipitation clouds with a length longer than 100 km and a width wider than 90 km is less than 1%. Most of the precipitation cloud exhibits a shape between square and long strips in the horizontal direction and lanky in the vertical direction. The average rainfall intensity of precipitation clouds is between 0.5 and 6 mm h−1. The average length and width of precipitation clouds show a logarithmic, linear relationship. The distribution of raindrops in precipitation clouds is relatively compact. With the expansion of the area, the precipitation clouds gradually become squatty. The relationship between physical and geometric parameters of precipitation clouds shows that with the precipitation cloud area expanding, the average rainfall rate of precipitation clouds also increases. Heavy convective rainfall is more likely to occur in larger precipitation clouds. For the precipitation clouds of the same size, the area fraction and contribution of convective precipitation are lower than that of stratiform precipitation.

scholarly journals Transition of the Rainfall Characteristics Related to the Moistening of the Land Surface over the Central Tibetan Plateau during the Summer of 1998

2006 ◽  
Vol 134 (11) ◽  
pp. 3230-3247 ◽  
Author(s):  
Hiroyuki Yamada ◽  
Hiroshi Uyeda
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Large Scale ◽  
Intraseasonal Variability ◽  
Surface Heat ◽  
Near Surface ◽  
Rainfall Characteristics ◽  
Central Tibetan Plateau ◽  
Rain Events ◽  
Heat Low

Abstract This paper describes a transition of rainfall characteristics related to the moistening of the land surface over the central Tibetan Plateau. This transition was observed three weeks after the onset of the summer rainy season of 1998. The objective is to clarify the potential of the plateau surface to modify the characteristics of monsoon rainfall. Summer rain events were first separated according to large-scale conditions into three types: one with a near-surface heat low and a Tibetan upper high, one with a near-surface low associated with a midlatitude trough, and one without a near-surface low. The first type was studied in further detail because of its intraseasonal variability in the rainfall amount (from 2.8 mm day−1 in June to 5.7 mm day−1 in August). The smaller amounts of the diurnal rain in June than July are related to the evaporation of precipitation within a drier and deeper subcloud layer. The moistening of this layer was related to the increase in the soil moisture and activation of vegetation. These results suggest a significant impact of the plateau surface upon the modification of the rainfall characteristics. This impact is the largest under the condition with a near-surface heat low forming due to strong solar heating.

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