scholarly journals A Cloud and Precipitation Feature Database from Nine Years of TRMM Observations

2008 ◽  
Vol 47 (10) ◽  
pp. 2712-2728 ◽  
Author(s):  
Chuntao Liu ◽  
Edward J. Zipser ◽  
Daniel J. Cecil ◽  
Stephen W. Nesbitt ◽  
Steven Sherwood
Keyword(s):  
Imaging System ◽  
Central Africa ◽  
Tropical Rainfall Measuring Mission ◽  
Intensity Measures ◽  
Microwave Brightness Temperature ◽  
Freezing Level ◽  
Maximum Reflectivity ◽  
Horizontal Size ◽  
Microwave Imager ◽  
Feature Database

Abstract An event-based method of analyzing the measurements from multiple satellite sensors is presented by using observations of the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR), Microwave Imager (TMI), Visible and Infrared Scanner (VIRS), and Lightning Imaging System (LIS). First, the observations from PR, VIRS, TMI, and LIS are temporally and spatially collocated. Then the cloud and precipitation features are defined by grouping contiguous pixels using various criteria, including surface rain, cold infrared, or microwave brightness temperature. The characteristics of measurements from different sensors inside these features are summarized. Then, climatological descriptions of many properties of the identified features are generated. This analysis method condenses the original information of pixel-level measurements into the properties of events, which can greatly increase the efficiency of searching and sorting the observed historical events. Using the TRMM cloud and precipitation feature database, the regional variations of rainfall contribution by features with different size, intensity, and PR reflectivity vertical structure are shown. Above the freezing level, land storms tend to have larger 20-dBZ area and reach higher altitude than is the case for oceanic storms, especially those land storms over central Africa. Horizontal size and the maximum reflectivity of oceanic storms decrease with altitude. For land storms, these intensity measures increase with altitude between 2 km and the freezing level and decrease more slowly with altitude above the freezing level than for ocean storms.

scholarly journals Relating Passive 37-GHz Scattering to Radar Profiles in Strong Convection

2011 ◽  
Vol 50 (1) ◽  
pp. 233-240 ◽  
Author(s):  
Daniel J. Cecil
Keyword(s):  
Central Africa ◽  
Tropical Rainfall Measuring Mission ◽  
The United States ◽  
Phase Layer ◽  
Tropical Ocean ◽  
Convective Systems ◽  
Freezing Level ◽  
Brightness Temperatures ◽  
Microwave Imager ◽  
Ice Water

Abstract Tropical Rainfall Measuring Mission (TRMM) Microwave Imager and precipitation radar measurements are examined for strong convective systems. Storms having similar values of minimum 37-GHz polarization-corrected temperature (PCT) are grouped together, and their vertical profiles of maximum radar reflectivity are composited. Lower 37-GHz PCT corresponds to stronger radar profiles (high reflectivity through a deep layer), but characteristic profiles for a given 37-GHz PCT are different for deep tropical ocean, deep tropical land, subtropical ocean, and subtropical land regions. Tropical oceanic storms have a sharper decrease of reflectivity just above the freezing level than storms from other regions with the same brightness temperature. Storms from subtropical land regions have the slowest decrease of reflectivity with height and the greatest mixed-phase-layer ice water content (IWC). Linear fits of 37-GHz PCT versus IWC for each region are used to scale the brightness temperatures. Counts of storms with these scaled brightness temperatures below certain thresholds suggest that not as many of the strongest storms occur in central Africa as in subtropical parts of South America, the United States, and central Asia.

scholarly journals Regional Differences in Overland Rainfall Estimation from PR-Calibrated TMI Algorithm

2005 ◽  
Vol 44 (2) ◽  
pp. 189-205 ◽  
Author(s):  
Tufa Dinku ◽  
Emmanouil N. Anagnostou
Keyword(s):  
Regional Differences ◽  
Rain Rate ◽  
Central Africa ◽  
Tropical Rainfall Measuring Mission ◽  
Error Statistics ◽  
Southern Plains ◽  
Significant Difference ◽  
Current Algorithm ◽  
Microwave Imager ◽  
Trmm Microwave Imager

Abstract The Tropical Rainfall Measuring Mission (TRMM) satellite carries a combination of active [precipitation radar (PR)] and multichannel passive microwave [the TRMM Microwave Imager (TMI)] sensors, which advance our ability to estimate rainfall over land. Rain retrieval from the TRMM PR is associated with an unprecedented accuracy and resolution but is limited in terms of sampling because of the narrow PR swath width (215 km). TMI provides wider coverage (760 km), but its observations are associated with a more complex relationship to precipitation in comparison with PR (especially over land). The PR rain estimates are used here for calibrating an overland TMI rain algorithm. The algorithm consists of 1) multichannel-based rain screening and convective/stratiform (C/S) classification schemes, and 2) nonlinear (linear) regressions for the rain-rate retrieval of stratiform (convective) rain regimes. This study examines regional differences in the algorithm performance. Four geographic regions consisting of central Africa (AFC), the Amazon (AMZ), the U.S. southern Plains (USA), and the Ganges–Brahmaputra–Meghna River basin (GBM) in south Asia are selected. Data from three summer months of 2000 and 2001 are used for calibration; validation is done using summer 2002 data. The current algorithm is also compared with the latest [version 6 (V6)] TRMM 2A12 product in terms of rain detection, and rain-rate retrieval error statistics on the basis of PR reference rainfall. The performance of the algorithm is different for the different regions. For instance, the reduction in random error (relative to 2A12 V6) is about 24%, 36%, 57%, and 165% for USA, AFC, AMZ, and GBM, respectively. However, significant difference between global (the four regions combined) and regional calibration is observed only for the GBM region.

Effects of TRMM Boost on Oceanic Rainfall Estimates Based on Microwave Emission Brightness Temperature Histograms (METH)

2008 ◽  
Vol 25 (10) ◽  
pp. 1888-1893 ◽  
Author(s):  
Dong-Bin Shin ◽  
Long S. Chiu
Keyword(s):  
Brightness Temperature ◽  
Correction Factor ◽  
Rain Rate ◽  
Incidence Angle ◽  
Tropical Rainfall Measuring Mission ◽  
Microwave Emission ◽  
Freezing Level ◽  
The Difference ◽  
Microwave Imager ◽  
Rain Rates

Abstract A physical–statistical algorithm for estimating space–time average oceanic rainfall has been applied to microwave measurements taken by the Special Sensor Microwave Imager (SSM/I) on board the Defense Meteorological Satellite Program (DMSP) satellites and the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) on board the TRMM satellite. The algorithm is based on Microwave Emission Brightness Temperature Histograms (METH) and produces monthly rainfall over 5° × 5° latitude–longitude boxes as a TRMM standard product (3A11). The TRMM satellite was boosted from an altitude of 350–402 km in August 2001 to extend its mission life. The orbit boost affected the orbital parameters, rain-rate–brightness temperature relations, and then rain-rate parameters. Using oceanic rain rates derived from SSM/I, the difference between 3A11 and SSM/I for the preboost and postboost periods was analyzed. The difference shows a significant jump from the preboost to the postboost data if no adjustments were made for the postboost TRMM data. The jumps in rain-rate parameters are attributed to the changes in earth’s incidence angle of TMI, affecting the brightness temperature in the TMI channels, the retrieved altitude of the freezing level, and the beam-filling correction factor. The changes in the brightness temperature (and freezing level) estimates and the beam-filling correction factor accounted for differences of approximately 4.9% and 1.5%, respectively. After the orbital and radiometric parameters are corrected for the boost, there is no detectable jump between the pre- and postboost 3A11 rain rates. The intersatellite calibration results demonstrate the robustness of the technique in producing a long record of climate-scale oceanic rainfall.

scholarly journals Combined Space and Ground Radars for Improving Quantitative Precipitation Estimations in the Eastern Downstream Region of the Tibetan Plateau. Part I: Variability in the Vertical Structure of Precipitation in ChuanYu Analyzed from Long-Term Spaceborne Observations by TRMM PR

2017 ◽  
Vol 56 (8) ◽  
pp. 2259-2274 ◽  
Author(s):  
Lingzhi Zhong ◽  
Rongfang Yang ◽  
Lin Chen ◽  
Yixin Wen ◽  
Ruiyi Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Vertical Structure ◽  
Tropical Rainfall Measuring Mission ◽  
Convective Precipitation ◽  
The Tibetan Plateau ◽  
Surface Precipitation ◽  
Freezing Level ◽  
Maximum Reflectivity ◽  
Downstream Region ◽  
Stratiform Precipitation

AbstractThis study presents a statistical analysis of the variability of the vertical structure of precipitation in the eastern downstream region of the Tibetan Plateau as measured by the Precipitation Radar (PR) on the National Aeronautics and Space Administration Tropical Rainfall Measuring Mission (TRMM) satellite. Data were analyzed over an 11-yr time span (January 2004–December 2014). The results show the seasonal and spatial variability of the storm height, freezing level, and bright band for different types of precipitation as well as the characteristics of intensity-related and type-related vertical profiles of reflectivity (VPR). Major findings were as follows: About 90% of the brightband peak reflectivity of stratiform precipitation was less than 32 dBZ, and 40% of the maximum reflectivity of convective precipitation exceeded 35 dBZ. The intensity of surface rainfall rates also depended on the shapes of VPRs. For stratiform precipitation, ice–snow aggregation was faster during moderate and heavy rainfall than it was in light rainfall. Since both the moisture and temperature are lower in winter, the transformation efficiency of hydrometeors becomes slower. Typical Ku-band representative climatological VPRs (CPRs) for stratiform precipitation have been created on the basis of the integration of normalized VPR shape for the given area and the rainfall intensity. All of the findings indicate that the developed CPRs can be used to improve surface precipitation estimates in regions with complex terrain where the ground-based radar net has limited visibility at low levels.

scholarly journals Understanding the Sources of Satellite Passive Microwave Rainfall Retrieval Systematic Errors Over Land

2017 ◽  
Vol 56 (3) ◽  
pp. 597-614 ◽  
Author(s):  
Veljko Petković ◽  
Christian D. Kummerow
Keyword(s):  
Central Africa ◽  
Tropical Rainfall Measuring Mission ◽  
Systematic Difference ◽  
Passive Microwave ◽  
System Structure ◽  
Test Bed ◽  
Organization Level ◽  
Microwave Imager ◽  
Trmm Microwave Imager ◽  
Rainfall Estimates

AbstractAnalyses of the Tropical Rainfall Measuring Mission (TRMM) satellite rainfall estimates reveal a substantial disagreement between its active [Precipitation Radar (PR)] and passive [TRMM Microwave Imager (TMI)] sensors over certain regions. This study focuses on understanding the role of the synoptic state of atmosphere in these discrepancies over land regions where passive microwave (PMW) retrievals are limited to scattering signals. As such the variability in the relationship between the ice-induced scattering signal and the surface rainfall is examined. Using the Amazon River and central Africa regions as a test bed, it is found that the systematic difference seen between PR and TMI rainfall estimates is well correlated with both the precipitating system structure and the level of its organization. Relying on a clustering technique to group raining scenes into three broad but distinct organizational categories, it is found that, relative to the PR, deep-organized systems are typically overestimated by TMI while the shallower ones are underestimated. Results suggest that the storm organization level can explain up to 50% of the regional systematic difference between the two sensors. Because of its potential for retrieval improvement, the ability to forecast the level of systems organization is tested. The state of the atmosphere is found to favor certain storm types when constrained by CAPE, wind shear, dewpoint depression, and vertical humidity distribution. Among other findings, the observations reveal that the ratio between boundary layer and midtropospheric moisture correlates well with the organization level of convection. If adjusted by the observed PR-to-TMI ratio under a given environment, the differences between PMW and PR rainfall estimates are diminished, at maximum, by 30% in RMSE and by 40% in the mean.

scholarly journals Cross Validation of Rainfall Characteristics Estimated from the TRMM PR, a Combined PR–TMI Algorithm, and a C-POL Ground Radar during the Passage of Tropical Cyclone and Nontropical Cyclone Events over Darwin, Australia

2018 ◽  
Vol 35 (12) ◽  
pp. 2339-2358 ◽  
Author(s):  
Anil Deo ◽  
S. Joseph Munchak ◽  
Kevin J. E. Walsh
Keyword(s):  
Tropical Cyclone ◽  
Tropical Rainfall Measuring Mission ◽  
Rainfall Rate ◽  
Rainfall Characteristics ◽  
Significant Difference ◽  
Median Volume ◽  
Precipitation Type ◽  
Correct Direction ◽  
Microwave Imager ◽  
Trmm Microwave Imager

AbstractThis study cross validates the radar reflectivity Z; the rainfall drop size distribution parameter (median volume diameter Do); and the rainfall rate R estimated from the Tropical Rainfall Measuring Mission (TRMM) satellite Precipitation Radar (PR), a combined PR and TRMM Microwave Imager (TMI) algorithm (COM), and a C-band dual-polarized ground radar (GR) for TRMM overpasses during the passage of tropical cyclone (TC) and non-TC events over Darwin, Australia. Two overpass events during the passage of TC Carlos and 11 non-TC overpass events are used in this study, and the GR is taken as the reference. It is shown that the correspondence is dependent on the precipitation type whereby events with more (less) stratiform rainfall usually have a positive (negative) bias in the reflectivity and the rainfall rate, whereas in the Do the bias is generally positive but small (large). The COM reflectivity estimates are similar to the PR, but it has a smaller bias in the Do for most of the greater stratiform events. This suggests that combining the TMI with the PR adjusts the Do toward the “correct” direction if the GR is taken as the reference. Moreover, the association between the TRMM estimates and the GR for the two TC events, which are highly stratiform in nature, is similar to that observed for the highly stratiform non-TC events (there is no significant difference), but it differs considerably from that observed for the majority of the highly convective non-TC events.

Combined Radar and Radiometer Analysis of Precipitation Profiles for a Parametric Retrieval Algorithm

2005 ◽  
Vol 22 (7) ◽  
pp. 909-929 ◽  
Author(s):  
Hirohiko Masunaga ◽  
Christian D. Kummerow
Keyword(s):  
A Priori ◽  
Three Dimensional ◽  
Tropical Rainfall Measuring Mission ◽  
Dimensional Structure ◽  
Retrieval Algorithm ◽  
Brightness Temperatures ◽  
Precipitation Measurement ◽  
Microwave Imager ◽  
Trmm Microwave Imager ◽  
Global Precipitation

Abstract A methodology to analyze precipitation profiles using the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and precipitation radar (PR) is proposed. Rainfall profiles are retrieved from PR measurements, defined as the best-fit solution selected from precalculated profiles by cloud-resolving models (CRMs), under explicitly defined assumptions of drop size distribution (DSD) and ice hydrometeor models. The PR path-integrated attenuation (PIA), where available, is further used to adjust DSD in a manner that is similar to the PR operational algorithm. Combined with the TMI-retrieved nonraining geophysical parameters, the three-dimensional structure of the geophysical parameters is obtained across the satellite-observed domains. Microwave brightness temperatures are then computed for a comparison with TMI observations to examine if the radar-retrieved rainfall is consistent in the radiometric measurement space. The inconsistency in microwave brightness temperatures is reduced by iterating the retrieval procedure with updated assumptions of the DSD and ice-density models. The proposed methodology is expected to refine the a priori rain profile database and error models for use by parametric passive microwave algorithms, aimed at the Global Precipitation Measurement (GPM) mission, as well as a future TRMM algorithms.

scholarly journals The Diurnal Cycle of Cloud-Top Height and Cloud Cover over the Southeastern Pacific as Observed by GOES-10

2013 ◽  
Vol 70 (8) ◽  
pp. 2393-2408 ◽  
Author(s):  
David Painemal ◽  
Patrick Minnis ◽  
Larry O'Neill
Keyword(s):  
Boundary Layer ◽  
Mixed Boundary ◽  
Phase Speed ◽  
Tropical Rainfall Measuring Mission ◽  
Sea Breeze ◽  
Air Entrainment ◽  
Liquid Water Path ◽  
Diurnal Cycles ◽  
Southeastern Pacific ◽  
Microwave Imager

Abstract The diurnal cycles in cloud-top height Htop and cloud fraction (CF) in the southeastern Pacific stratocumulus region were determined for October–November 2008 by analyzing data from Geostationary Operational Environmental Satellite-10 (GOES-10) according to a diurnal/semidiurnal harmonic fitting technique. The value of Htop was obtained by applying a formula based on a linear regression of the differences between GOES-10 cloud-top temperature and Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) satellite sea surface temperature, with a common 0.25° × 0.25° spatial resolution. A satellite liquid water path (LWP) climatology complemented this dataset. Southwestward transects of Htop and LWP anomalies reveal a coherent propagating signal from the coast in the afternoon, with a typical phase speed of 25 m s−1. This pattern is preceded by a subsidence wave that reaches its peak a few hours before the maximum in Htop and LWP anomalies. Coincident increases in LWP and Htop after the subsidence wave passes suggest that the boundary layer deepening promotes cloud thickening and increased LWP, which are likely maintained through a well-mixed boundary layer and sufficient moisture fluxes that can counteract the effect of dry air entrainment. The interference between the radiatively and subsidence wave–driven cycles gives rise to a semidiurnal cycle in Htop along the coast. While the semidiurnal amplitude is near 80 m close to the coast with a fraction of explained variance greater than 0.4, it decreases to 30 m offshore (80°W). Similar to Htop, CF also exhibits contrasting zonal differences, but with a smaller semidiurnal component. The phase of the semidiurnal harmonic resembles the subsidence propagation westward, and the noticeable land–sea breeze circulation at 26°S that extends 200 km offshore.

scholarly journals Comparison of SMMR and SSM/I passive microwave data collected over Antarctica

1993 ◽  
Vol 17 ◽  
pp. 131-136 ◽  
Author(s):  
Kenneth C. Jezek ◽  
Carolyn J. Merry ◽  
Don J. Cavalieri
Keyword(s):  
Brightness Temperature ◽  
Microwave Radiometer ◽  
Correlated Data ◽  
Data Sets ◽  
Microwave Brightness Temperature ◽  
Brightness Temperatures ◽  
Scatter Plots ◽  
Microwave Imager ◽  
Highly Correlated ◽  
The Antarctic

Spaceborne data are becoming sufficiently extensive spatially and sufficiently lengthy over time to provide important gauges of global change. There is a potentially long record of microwave brightness temperature from NASA's Scanning Multichannel Microwave Radiometer (SMMR), followed by the Navy's Special Sensor Microwave Imager (SSM/I). Thus it is natural to combine data from successive satellite programs into a single, long record. To do this, we compare brightness temperature data collected during the brief overlap period (7 July-20 August 1987) of SMMR and SSM/I. Only data collected over the Antarctic ice sheet are used to limit spatial and temporal complications associated with the open ocean and sea ice. Linear regressions are computed from scatter plots of complementary pairs of channels from each sensor revealing highly correlated data sets, supporting the argument that there are important relative calibration differences between the two instruments. The calibration scheme was applied to a set of average monthly brightness temperatures for a sector of East Antarctica.

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.

Sign in / Sign up

Export Citation Format

Share Document