scholarly journals Studies of General Precipitation Features with TRMM PR Data: An Extensive Overview

2019 ◽  
Vol 11 (1) ◽  
pp. 80 ◽  
Author(s):  
Nan Li ◽  
Zhenhui Wang ◽  
Xi Chen ◽  
Geoffrey Austin
Keyword(s):  
Three Dimensional ◽  
Tropical Rainfall Measuring Mission ◽  
Radar Data ◽  
Future Prospects ◽  
Precipitation Radar ◽  
Tropical Regions ◽  
Existing Problems ◽  
Rain Gauges ◽  
Trmm Pr ◽  
Continuous Rainfall

The Precipitation Radar (PR), the first space-borne precipitation radar onboard the Tropical Rainfall Measuring Mission (TRMM) satellite, could observe three-dimensional precipitation in global tropical regions and acquire continuous rainfall information with moderate temporal and high spatial resolutions. TRMM PR had carried out 17 years of observations and ended collecting data in April, 2015. So far, comprehensive and abundant research results related to the application of PR data have been analyzed in the current literature, but overall precipitation features are not yet identified, a gap that this review intends to fill. Studies on comparisons with ground-based radars and rain gauges are first introduced to summarize the reliability of PR observations or estimates. Then, this paper focuses on general precipitation features abstracted from about 130 studies, from 2000 to 2018, regarding lightning analysis, latent heat retrieval, and rainfall observation by PR data. Finally, we describe the existing problems and limitations as well as the future prospects of the space-borne precipitation radar data.

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.

scholarly journals Effect of TRMM Orbit Boost on Radar Reflectivity Distributions

2010 ◽  
Vol 27 (7) ◽  
pp. 1247-1254 ◽  
Author(s):  
David A. Short ◽  
Kenji Nakamura
Keyword(s):  
Probability Distributions ◽  
Gaussian Function ◽  
Tropical Rainfall Measuring Mission ◽  
Radar Reflectivity ◽  
Response Functions ◽  
Precipitation Radar ◽  
Mathematical Properties ◽  
Trmm Pr ◽  
Before And After ◽  
Basic Characteristics

Abstract Probability distributions of measured radar reflectivity from the precipitation radar (PR) on board the Tropical Rainfall Measuring Mission (TRMM) satellite show a small, counterintuitive increase in the midrange, 20–34 dBZ, when comparing data from periods before and after the orbit altitude was boosted in August 2001. Data from two 2-yr time periods, 1999–2000 (preboost) and 2002–03 (postboost), show statistically significant differences of 2%–3% at altitudes of 2, 4, and 10 km and for path-averaged reflectivity. The bivariate Gaussian function, used to model idealized radar response functions, has mathematical properties that indicate an increase in field-of-view (FOV) size associated with an increase in satellite altitude can be expected to result in a narrowing of observed dBZ distributions, with a resulting increase in midrange values. Numerical simulations with echo areas much smaller and larger than the TRMM PR FOV before (4.3 km) and after (5.0 km) boost are used to demonstrate basic characteristics of the observed and expected distribution changes.

scholarly journals Where the Least Rainfall Occurs in the Sahara Desert, the TRMM Radar Reveals a Different Pattern of Rainfall Each Season

2014 ◽  
Vol 27 (18) ◽  
pp. 6919-6939 ◽  
Author(s):  
Owen A. Kelley
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Seasonal Patterns ◽  
Sahara Desert ◽  
Precipitation Radar ◽  
Light Rain ◽  
Rain Gauges ◽  
The North ◽  
Imaging Sensor ◽  
Summer Rain ◽  
Rainfall Climatology

Abstract Some previous studies were unable to detect seasonal organization to the rainfall in the Sahara Desert, while others reported seasonal patterns only in the less-arid periphery of the Sahara. In contrast, the precipitation radar on the Tropical Rainfall Measuring Mission (TRMM) satellite detects four rainy seasons in the part of the Sahara where the TRMM radar saw the least rainfall during a 15-yr period (1998–2012). According to the TRMM radar, approximately 20°–27°N, 22°–32°E is the portion of the Sahara that has the lowest average annual rain accumulation (1–5 mm yr−1). Winter (January and February) has light rain throughout this region but more rain to the north over the Mediterranean Sea. Spring (April and May) has heavier rain and has lightning observed by the TRMM Lightning Imaging Sensor (LIS). Summer rain and lightning (July and August) occur primarily south of 23°N. At a maximum over the Red Sea, autumn rain and lightning (October and November) can be heavy in the northeastern portion of the study area, but these storms are unreliable: that is, the TRMM radar detects such storms in only 6 of the 15 years. These four rainy seasons are each separated by a comparatively drier month in the monthly rainfall climatology. The few rain gauges in this arid region broadly agree with the TRMM radar on the seasonal organization of rainfall. This seasonality is reason to reevaluate the idea that Saharan rainfall is highly irregular and unpredictable.

Incorporating NASA Spaceborne Radar Data into NOAA National Mosaic QPE System for Improved Precipitation Measurement: A Physically Based VPR Identification and Enhancement Method

2013 ◽  
Vol 14 (4) ◽  
pp. 1293-1307 ◽  
Author(s):  
Yixin Wen ◽  
Qing Cao ◽  
Pierre-Emmanuel Kirstetter ◽  
Yang Hong ◽  
Jonathan J. Gourley ◽  
...  
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Radar Data ◽  
Cold Season ◽  
Dual Frequency ◽  
Surface Precipitation ◽  
Precipitation Measurement ◽  
Trmm Pr ◽  
Physically Based ◽  
Precipitation Estimation ◽  
Enhancement Method

Abstract This study proposes an approach that identifies and corrects for the vertical profile of reflectivity (VPR) by using Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) measurements in the region of Arizona and southern California, where the ground-based Next Generation Weather Radar (NEXRAD) finds difficulties in making reliable estimations of surface precipitation amounts because of complex terrain and limited radar coverage. A VPR identification and enhancement (VPR-IE) method based on the modeling of the vertical variations of the equivalent reflectivity factor using a physically based parameterization is employed to obtain a representative VPR at S band from the TRMM PR measurement at Ku band. Then the representative VPR is convolved with ground radar beam sampling properties to compute apparent VPRs for enhancing NEXRAD quantitative precipitation estimation (QPE). The VPR-IE methodology is evaluated with several stratiform precipitation events during the cold season and is compared to two other statistically based correction methods, that is, the TRMM PR–based rainfall calibration and a range ring–based adjustment scheme. The results show that the VPR-IE has the best overall performance and provides much more accurate surface rainfall estimates than the original ground-based radar QPE. The potential of the VPR-IE method could be further exploited and better utilized when the Global Precipitation Measurement Mission's dual-frequency PR is launched in 2014, with anticipated accuracy improvements and expanded latitude coverage.

scholarly journals Detectability and Configuration of Tropical Cyclone Eyes over the Western North Pacific in TRMM PR and IR Observations

2005 ◽  
Vol 133 (8) ◽  
pp. 2213-2226 ◽  
Author(s):  
Yasu-Masa Kodama ◽  
Takuya Yamada
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Tropical Rainfall Measuring Mission ◽  
Mature Stage ◽  
Precipitation Radar ◽  
Wind Speeds ◽  
Trmm Pr ◽  
Eye Diameter ◽  
Concentric Eyewalls

Abstract Statistics for 138 cases from 61 tropical cyclones over the western North Pacific during the five years from 1998 to 2002 were used to determine the detectability and configuration of tropical cyclone (TC) eyes and to reveal relations with TC intensity and life stages in satellite-based infrared (IR) and precipitation radar (PR) observations from the Tropical Rainfall Measuring Mission (TRMM). Tropical cyclone eyes were detectable in PR data in 89% of cases and in IR data in 37% of cases. Maximum sustained wind speeds in TCs were much greater when the eye was detected in both IR and PR data than in cases when the eye was detected only in PR data or when no eye was detected in either PR or IR data. An eye was detectable in both IR and PR data in the developing stage of only 18% of TCs although an eye was present in the PR data in 90% of cases. An eye was detected in both IR and PR data in 51% of the TCs during the mature stage. During the decaying stage, an eye was detected in both IR and PR data in 31% of cases. Eye diameter determined from PR observations was larger during the later stages. Most TCs had an eye less than 82.5 km in diameter during the developing stage. Tropical cyclone eyes embedded within concentric eyewalls appeared more frequently in the mature and decaying stages; this is consistent with findings from previous studies. In most cases, eye diameter was smaller in IR observations than in PR observations because an upper cloud shield extending from the eyewall partially covered the eye. For several TCs with concentric eye walls, however, eye diameter was smaller in PR observations. A shallow inner eyewall in the PR data and a deep outer eyewall in both IR and PR data characterized these cases.

scholarly journals Seasonal and Diurnal Variability of Rain Heights at An Equatorial Station

2015 ◽  
Vol 5 (5) ◽  
pp. 1134
Author(s):  
Abayomi Isiaka Yussuff ◽  
Nor Hisham Haji Khamis
Keyword(s):  
Radar Data ◽  
Rain Attenuation ◽  
Diurnal Variations ◽  
Precipitation Radar ◽  
Equatorial Station ◽  
Diurnal Variability ◽  
Seasonal And Diurnal Variations ◽  
Trmm Pr ◽  
One Year ◽  
Satellite Equipment

Seasonal and diurnal rain heights variation at Universiti Teknologi Malaysia, Johor was studied.<strong> </strong>Slant path rain attenuation prediction and modeling is crucial to satellite equipment design; a major input is the rain height. One year meteorological ground-based, S-band, 3D RAPIC precipitation radar data at 500m resolution sourced from the Malaysian Meteorological Department was complemented with two-year TRMM PR data sourced from JAXA Earth Observation Research Center. After filtering, sorting, extraction and decoding of the data, vertical reflectivity profiles were constructed; from which rain height parameters were extracted. TRMM PR processed monthly (3A25) and daily (2A23) rainfall precipitation data were similarly used to obtain rain height parameters to investigate the seasonal and diurnal variations. Results from this work suggested that rain height parameters are influenced by both seasonal and diurnal variations. Higher seasonal variability was observed during south-west and pre-southwest monsoons. Rain heights were also observed to be higher in the night than in the day time.

scholarly journals A novel algorithm for detection of precipitation in tropical regions using PMW radiometers

2015 ◽  
Vol 8 (3) ◽  
pp. 1217-1232 ◽  
Author(s):  
D. Casella ◽  
G. Panegrossi ◽  
P. Sanò ◽  
L. Milani ◽  
M. Petracca ◽  
...  
Keyword(s):  
Microwave Radiometer ◽  
Tropical Rainfall Measuring Mission ◽  
Probability Of Detection ◽  
Arid Land ◽  
False Alarms ◽  
Data Set ◽  
Tropical Regions ◽  
Brightness Temperatures ◽  
Trmm Pr ◽  
Novel Algorithm

Abstract. A novel algorithm for the detection of precipitation is described and tested. The algorithm is applicable to any modern passive microwave radiometer on board polar orbiting satellites independent of the observation geometry and channel frequency assortment. The algorithm is based on the application of canonical correlation analysis and on the definition of a threshold to be applied to the resulting linear combination of the brightness temperatures in all available channels. The algorithm has been developed using a 2-year data set of co-located Special Sensor Microwave Imager/Sounder (SSMIS) and Tropical Rainfall Measuring Mission precipitation radar (TRMM-PR) measurements and Advanced Microwave Sounding Unit (AMSU) Microwave Humidity Sounder and TRMM-PR measurements. This data set was partitioned into four classes depending on the background surface emissivity (vegetated land, arid land, ocean, and coast) with the same procedure applied for each surface class. In this paper we describe the procedure and evaluate the results in comparison with many well-known algorithms for the detection of precipitation. The algorithm shows a small rate of false alarms and superior detection capability; it can efficiently detect (probability of detection between 0.55 and 0.71) minimum rain rate varying from 0.14 mm h-1 (AMSU over ocean) to 0.41 (SSMIS over coast) with the remarkable result of 0.25 mm h-1 over arid land surfaces.

scholarly journals Comparisons of Reflectivities from the TRMM Precipitation Radar and Ground-Based Radars

2009 ◽  
Vol 26 (5) ◽  
pp. 857-875 ◽  
Author(s):  
Jianxin Wang ◽  
David B. Wolff
Keyword(s):  
Three Dimensional ◽  
Tropical Rainfall Measuring Mission ◽  
Horizontal Displacement ◽  
Marshall Islands ◽  
Precipitation Radar ◽  
Convective Rain ◽  
Ground Validation ◽  
Trmm Precipitation ◽  
Cartesian Coordinate ◽  
Global Precipitation

Abstract Given the decade-long and highly successful Tropical Rainfall Measuring Mission (TRMM), it is now possible to provide quantitative comparisons between ground-based radars (GRs) and the spaceborne TRMM precipitation radar (PR) with greater certainty over longer time scales in various tropical climatological regions. This study develops an automated methodology to match and compare simultaneous TRMM PR and GR reflectivities at four primary TRMM Ground Validation (GV) sites: Houston, Texas (HSTN); Melbourne, Florida (MELB); Kwajalein, Republic of the Marshall Islands (KWAJ); and Darwin, Australia (DARW). Data from each instrument are resampled into a three-dimensional Cartesian coordinate system. The horizontal displacement during the PR data resampling is corrected. Comparisons suggest that the PR suffers significant attenuation at lower levels, especially in convective rain. The attenuation correction performs quite well for convective rain but appears to slightly overcorrect in stratiform rain. The PR and GR observations at HSTN, MELB, and KWAJ agree to about ±1 dB on average with a few exceptions, whereas the GR at DARW requires +1 to −5 dB calibration corrections. One of the important findings of this study is that the GR calibration offset is dependent on the reflectivity magnitude. Hence, it is proposed that the calibration should be carried out by using a regression correction rather than by simply adding an offset value to all GR reflectivities. This methodology is developed to assist TRMM GV efforts to improve the accuracy of tropical rain estimates, but can also be applied to the proposed Global Precipitation Measurement and other related activities over the globe.

scholarly journals Validation of TRMM Precipitation Radar through Comparison of Its Multiyear Measurements with Ground-Based Radar

2009 ◽  
Vol 48 (4) ◽  
pp. 804-817 ◽  
Author(s):  
Liang Liao ◽  
Robert Meneghini
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Heavy Rain ◽  
Radar Data ◽  
Precipitation Radar ◽  
Convective Storms ◽  
Conditional Mean ◽  
Conditional Basis ◽  
Trmm Precipitation ◽  
Rain Rates ◽  
Overlap Area

Abstract A procedure to accurately resample spaceborne and ground-based radar data is described and then is applied to the measurements taken from the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) and the ground-based Weather Surveillance Radar-1988 Doppler (WSR-88D or WSR) for the validation of the PR measurements and estimates. Through comparisons with the well-calibrated, nonattenuated WSR at Melbourne, Florida, for the period 1998–2007, the calibration of the PR aboard the TRMM satellite is checked using measurements near the storm top. Analysis of the results indicates that the PR, after taking into account differences in radar reflectivity factors between the PR and WSR, has a small positive bias of 0.8 dB relative to the WSR, implying a soundness of the PR calibration in view of the uncertainties involved in the comparisons. Comparisons between the PR and WSR reflectivities are also made near the surface for evaluation of the attenuation-correction procedures used in the PR algorithms. It is found that the PR attenuation is accurately corrected in stratiform rain but is underestimated in convective rain, particularly in heavy rain. Tests of the PR estimates of rainfall rate are conducted through comparisons in the overlap area between the TRMM overpass and WSR scan. Analyses of the data are made both on a conditional basis, in which the instantaneous rain rates are compared only at those pixels at which both the PR and WSR detect rain, and an unconditional basis, in which the area-averaged rain rates are estimated independently for the PR and WSR. Results of the conditional rain comparisons show that the PR-derived rain is about 9% greater and 19% less than the WSR estimates for stratiform and convective storms, respectively. Overall, the PR tends to underestimate the conditional mean rain rate by 8% for all rain categories, a finding that conforms to the results of the area-averaged rain (unconditional) comparisons.

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