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Proceedings ArticleDOI

Retrieval of rainfall from the MADRAS microwave imager of Megha-Tropiques

TL;DR: This lecture will chronicle the efforts taken towards the development of robust rainfall retrieval techniques from the Indo-French mission Megha-Tropiques microwave imager due to be launched shortly.
Abstract: Microwave radiation with the inherent advantage of its ability to partially penetrate clouds is ideally suited for remote measurements of rainfall, especially over the oceanic regions. The retrieval problem is of great practical interest, as precipitation over the oceans has to be necessarily remotely sensed. More importantly, precipitation is also a crucial input in many weather and climate models. IIT Madras has developed over the last ten years an in-house polarized microwave radiation transfer model (Micro- Tropiques) along with candidate retrieval strategies for the retrieval of rainfall for possible use in the multi frequency (18.7 GHz, 23.8 GHz, 36.5 GHz, 89 GHz and 157 GHz) Microwave Analysis and Detection of Rain and Atmospheric Structures (MADRAS) microwave imager of the Indo-French mission Megha-Tropiques (MT) due to be launched shortly. This lecture will chronicle the efforts taken towards the development of robust rainfall retrieval techniques from the MT data.
Citations
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10 May 2010
TL;DR: The Megha-Tropiques satellite as mentioned in this paper is devoted to the study of the atmospheric water cycle in the tropics and its relation to the radiative budget, which is aimed to study both the energy and water budget of the intertropical band and the life cycle of the convective complexes in the Tropics.
Abstract: The Megha-Tropiques satellite is devoted to the study of the atmospheric water cycle in the tropics and its relation to the radiative budget. It is aiming to study both the energy and water budget of the intertropical band and the life cycle of the convective complexes in the Tropics. The orbit of the satellite allows it to sample several times per day the zone from 23°N to 23°S, where most of the precipitation of the planet and large energy exchanges occur. The three instruments of the mission are a microwave imager, a microwave water vapor sounder and a radiative budget instrument. The launch of this mission by an Indian Rocket is foreseen in 2006-2007. It will hopefully coincide with the time frame of the Global Precipitation Mission, allowing to improve its tropical coverage.

24 citations

Dissertation
01 Jan 2012

8 citations


Cites background or methods from "Retrieval of rainfall from the MADR..."

  • ...The two microwave instruments on board are Microwave Analysis and Detection of Rain and Atmospheric Structures (MADRAS) [255, 256] and SAPHIR (Sondeur Atmospherique du Pro l d'Humidite Intertropicale par Radiometrie)....

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  • ...Rain algorithms are described for the MADRAS instrument [255, 256] and for atmospheric sounders [89, 257]....

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Journal ArticleDOI
TL;DR: This paper presents a new strategy to correct the Earth data corrupted by spurious samples that are randomly included in the multiplexed data stream provided by the MADRAS instrument, relying on the construction of a trellis associated with each scan of the multichannel image.
Abstract: This paper presents a new strategy to correct the Earth data corrupted by spurious samples that are randomly included in the multiplexed data stream provided by the MADRAS instrument. The proposed strategy relies on the construction of a trellis associated with each scan of the multichannel image, modeling the possible occurrences of these erroneous data. A specific weight that promotes the smooth behavior of the signals recorded in each channel is assigned to each transition between trellis states. The joint detection and correction of the erroneous data are conducted using a dynamic programming algorithm for minimizing the overall cost function throughout the trellis. Simulation results obtained on synthetic and real MADRAS data demonstrate the effectiveness of the proposed solution.

1 citations

References
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Journal ArticleDOI
TL;DR: In this article, the authors present a reference guide to users wishing to make use of the Tropical Rainfall Measuring Mission data, which covers each of the three primary rainfall instruments: the passive microwave radiometer, the precipitation radar, and the Visible and Infrared Radiometer System on board the spacecraft.
Abstract: This note is intended to serve primarily as a reference guide to users wishing to make use of the Tropical Rainfall Measuring Mission data. It covers each of the three primary rainfall instruments: the passive microwave radiometer, the precipitation radar, and the Visible and Infrared Radiometer System on board the spacecraft. Radiometric characteristics, scanning geometry, calibration procedures, and data products are described for each of these three sensors.

2,317 citations

01 May 2002
TL;DR: PCA is a useful statistical technique that has found application in fields such as face recognition and image compression, and is a common technique for finding patterns in data of high dimension.
Abstract: Introduction This tutorial is designed to give the reader an understanding of Principal Components Analysis (PCA). PCA is a useful statistical technique that has found application in fields such as face recognition and image compression, and is a common technique for finding patterns in data of high dimension. Before getting to a description of PCA, this tutorial first introduces mathematical concepts that will be used in PCA. It covers standard deviation, covariance, eigenvec-tors and eigenvalues. This background knowledge is meant to make the PCA section very straightforward, but can be skipped if the concepts are already familiar. There are examples all the way through this tutorial that are meant to illustrate the concepts being discussed. If further information is required, the mathematics textbook " Elementary Linear Algebra 5e " ISBN 0-471-85223-6 is a good source of information regarding the mathematical background .

1,926 citations


"Retrieval of rainfall from the MADR..." refers background in this paper

  • ...However, a few parameters are sufficient in many such problems to reproduce the same information without compromising on the accuracy (Smith [14])....

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Journal ArticleDOI
TL;DR: In this article, a Bayesian approach was proposed for retrieving the precipitation and vertical hydrometeor profiles from downward viewing radiometers based on a prior probability density function of rainfall profiles, which is computationally much less expensive than previous profiling schemes and has been designed specifically to allow for tractability of assumptions.
Abstract: Presents a computationally simple technique for retrieving the precipitation and vertical hydrometeor profiles from downward viewing radiometers. The technique is computationally much less expensive than previous profiling schemes and has been designed specifically to allow for tractability of assumptions. In this paper, the emphasis is placed upon passive microwave applications, but the combination of passive with active microwave sensors, infrared sensors, or other a priori information can be adapted easily to the framework described. The technique is based upon a Bayesian approach. The authors use many realizations of the Goddard Cumulus Ensemble model to establish a prior probability density function of rainfall profiles. Detailed three-dimensional radiative transfer calculations are used to determine the upwelling brightness temperatures from the cloud model to establish the similarity of radiative signatures and thus the probability that a given profile is actually observed. In this study, the authors show that good results may be obtained by weighting profiles from the prior probability density function according to their deviation from the observed brightness temperatures. Examples of the retrieval results are shown for oceanic as well as land situations. Microwave data from the Advanced Microwave Precipitation Radiometer (AMPR) instrument are used to illustrate the retrieval structure results for high-resolution data while SSM/I is used to illustrate satellite applications. Simulations are performed to compare the expected retrieval performance of the SSM/I instrument with that of the upcoming TMI instrument aboard the Tropical Rainfall Measuring Mission (TRMM) to be launched in August 1997. These simulations show that correlations of /spl sim/0.77 may be obtained for 10-km retrievals of the integrated liquid water content based upon SSM/I channels. This correlation increases to /spl sim/0.90 for the same retrievals using the TMI channels and resolution. Due to the lack of quantitative validation data, hydrometeor profiles cannot be compared directly but are instead converted to an equivalent reflectivity structure and compared to existing radar observations where possible.

484 citations

Journal ArticleDOI
TL;DR: In this article, a plane-parallel polarized radiative transfer model was used to compute the radiance exiting a vertically inhomogeneous atmosphere containing randomly-oriented particles, where both solar and thermal sources of radiation were considered.
Abstract: A plane-parallel polarized radiative transfer model is described. The model is used to compute the radiance exiting a vertically inhomogeneous atmosphere containing randomly-oriented particles. Both solar and thermal sources of radiation are considered. A direct method of incorporating the polarized scattering information is combined with the doubling and adding method to produce a relatively simple formulation. Several numerical results are presented for verification and comparison.

360 citations


"Retrieval of rainfall from the MADR..." refers background in this paper

  • ...There are numerous solution techniques available in the literature to solve the vector radiative transfer model, of which Doubling and Adding method is very popular (Hansen [4], de Haan et al. [5], Evans and Stephens [3])....

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  • ...Following Evans and Stephens [3], the equation of radiative transfer in vector form (including polarization from the medium) that is applicable for microwave frequencies, known as Micro-Tropiques, is given by...

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  • ...THE EQUATION OF RADIATIVE TRANSFER Following Evans and Stephens [3], the equation of radiative transfer in vector form (including polarization from the medium) that is applicable for microwave frequencies, known as Micro-Tropiques, is given by 0 0 0 1 ~1 ~~~,~;, 4 ~ ,,,, 2 0 1 1 TB ddP d d II (1) Here the medium is assumed to be bounded by two parallel plates; earth’s surface at the bottom specified by its 1283978-1-4577-1005-6/11/$26.00 ©2011 IEEE IGARSS 2011 temperature, wind speed and salinity, and top of atmosphere in the top....

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