Potential of simultaneous dual-frequency radar altimeter measurements from TOPEX/Poseidon for rainfall estimation over oceans

Bhandari, S. M.; Varma, A. K.

doi:10.1016/0034-4257(96)00050-8

Cited by 13 publications

(12 citation statements)

References 10 publications

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“…Since the Arabian Sea covers a larger area, there are more observations in the scatter plots than for the Bay of Bengal, but the trends are nearly the same. The general trends are almost the same as linear distribution except a separate, nonlinear trend is seen immerging at around 200K in the 18 GHz channel and 240K in the 37 GHz channel. The possible reasons for such an ambiguity could be that the total rain is resulting from more than one type of cloud, Fig.…”

Section: Resultsmentioning

confidence: 57%

“…The correlations at 0.10, 0.25, and 0.50 are 0.38, 0.30, and 0.24, respectively. It shows that 21 GHz channel observations can explain more temporal variability than 18 GHz observations for all observations above 2 h. This is not true for the 37 GHz TB observations. Fig.…”

Section: Resultsmentioning

confidence: 66%

“…It reduces to 0.66 and 0.61 for 21 and 37 GHz, respectively, for the same temporal and spatial separation. When the spatial separation has been increased up to 0.25 and 0.50 for 18 GHz brightness temperatures, the correlation coefficient reduces to 0.64 and 0.40, respectively, and still further for 21 and 37 GHz. Fig.…”

Section: Resultsmentioning

confidence: 95%

“…As stated earlier, the rain attenuates the altimeter pulse. Heavy rain greatly reduces the strength of echo from the sea surface in the Ku band [18], and light rain tends to produce rapid changes in the strength of the echo as the altimeter crosses rain cells [15]. Both effects degrade the performance of the altimeter for topographic measurements.…”

Section: A Topex/poseidon Datamentioning

confidence: 99%

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Rain rate estimation from nadir-looking TOPEX/POSEIDON microwave radiometer (TMR) for correction of radar altimetric measurements

Varma

Gairola

Kishtawal

et al. 1999

IEEE Trans. Geosci. Remote Sensing

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Atmospheric liquid water, particularly in the form of rain, produces anomalies in the radar altimetric range measurements. Such features are observed as sudden large changes in radar backscatter as a means of identification. To quantify the rain that radar altimetric pulses encounter, the instantaneous rain estimation capability of the nadir looking multichannel microwave radiometer onboard the TOPEX/POSEIDON satellite is explored. The three frequency (18, 21, and 37 GHz) nadir looking TOPEX microwave radiometer (TMR) brightness temperature data are colocated with the special sensor microwave/imager (SSM/I) rain rates to find a new rain rate algorithm by regression over the Indian Sea. Among the colocated data on different spatial and temporal scales, the most restrictive criteria (< < <0.1 , < < <1 h apart) produce the best correlations between the SSM/I estimated rain rates and the TMR brightness temperatures. The TMR measurements, colocated with SSM/I, thus presents a nontraditional usage of nadir viewing microwave radiometer data for estimation of instantaneous rainfall for correction of the radar altimetric measurements over the oceans. This equation is further used to generate monthwise-averaged global rain rate mapsfor the year 1993. Typical rain rate maps for two contrasting seasons for the months of January and July 1993, during the northeast and southwest monsoon, respectively, are compared with similar maps of the SSM/I rain rate. It is found that all the major features of global rainfall are picked up accurately and reproduced by the TMR-based algorithm. The mean rainfall rate thus derived (totaling a month) also is analyzed with some simultaneous atmospheric and oceanic processes in mind, which couple each other through rainfall.Index Terms-DMSP-SSM/I, rain rate, TOPEX/POSEIDON altimeter, TOPEX microwave radiometer.

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 95%

Section: A Topex/poseidon Datamentioning

confidence: 99%

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Rain rate estimation from nadir-looking TOPEX/POSEIDON microwave radiometer (TMR) for correction of radar altimetric measurements

Varma

Gairola

Kishtawal

et al. 1999

IEEE Trans. Geosci. Remote Sensing

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“…In addition, application of such RA data from Topex and subsequent follow on missions have also been exploited for estimation of rainfall over the oceans for the first time by Bhandari and Varma (1996) and subsequently developed extensively by others (Chen et al,1997). TOPEX dual frequency Radar Altimeter (RA) mission was launched in 1992.…”

Section: Introductionmentioning

confidence: 99%

Spatial Coherence of winds and waves over the Arabian Sea and Bay of Bengal and their evolution during SW Monsoon: a novel application of along-track Radar Altimeter measurements from Space

Bhandari¹,

Shaeb

2014

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:We have examined, for the first time, the spatial coherence of oceanic parameters, namely, the ocean surface wind and significant wave height (SWH), using near-instantaneous along-track sampling over vast oceanic tracks provided by Poseidon-2 Radar Altimeter onboard Jason-1. The spatial coherence length scales over the Arabian Sea and the Bay of Bengal regions, derived using Auto correlation analysis, display interesting characteristics in relation to onset and evolution of SW Monsoon over India. The estimated spatial coherence scales are found to be of the order of 100-500 km. Generally, SWH coherence lengths over Arabian Sea are observed to increase from June to July during good monsoon year (2012). This trend is not followed for the poor monsoon year (2002). Similar trend is observed for spatial coherence scales for wind speed. The temporal evolution of analyzed spatial coherence scales of winds and waves over Arabian Sea clearly brings out the distinction between a 'good' (2012) and a 'poor' (2002) monsoon year. The spatial coherence lengths of these parameters over the Bay of Bengal are found to be shorter and do not show any systematic relation to onset and evolution of SW monsoon. Anisotropy in coherence lengths is also analyzed by treating ascending and descending tracks separately. Generally, the descending tracks measurements show higher spatial coherence lengths than the ascending ones. Like the spatial coherence scales, the anisotropy of the coherence scales over the Arabian Sea also mimics the behaviour of the strength of SW Monsoon.

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Measurement of Precipitation from Satellite Radiometers (Visible, Infrared, and Microwave): Physical Basis, Methods, and Limitations

Varma

2018

Remote Sensing of Aerosols, Clouds, and Precipitation

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Potential of simultaneous dual-frequency radar altimeter measurements from TOPEX/Poseidon for rainfall estimation over oceans

Cited by 13 publications

References 10 publications

Rain rate estimation from nadir-looking TOPEX/POSEIDON microwave radiometer (TMR) for correction of radar altimetric measurements

Rain rate estimation from nadir-looking TOPEX/POSEIDON microwave radiometer (TMR) for correction of radar altimetric measurements

Spatial Coherence of winds and waves over the Arabian Sea and Bay of Bengal and their evolution during SW Monsoon: a novel application of along-track Radar Altimeter measurements from Space

Measurement of Precipitation from Satellite Radiometers (Visible, Infrared, and Microwave): Physical Basis, Methods, and Limitations

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