The Experts below are selected from a list of 636 Experts worldwide ranked by ideXlab platform
Angelo Rubino - One of the best experts on this subject based on the ideXlab platform.
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Internal Waves Generated in the Straits of Gibraltar and Messina: Observations from Space
2015Co-Authors: Werner Alpers, Peter Brandt, Angelo RubinoAbstract:Abstract. The Straits of Gibraltar and Messina are areas where strong in-ternal solitary waves are generated by the interaction of tidal currents with shallow underwater ridges located within the straits. Remote sensing tech-niques and numerical simulations have been instrumental in studying the generation and propagation of internal solitary waves in these sea areas. It was a Synthetic Aperture Radar (SAR) image acquired by the American SEASAT Satellite in 1978 that first revealed that long internal waves are gen-erated in the Strait of Messina. Furthermore, SAR images acquired by the European Remote Sensing Satellite ERS-1 and ERS-2 have revealed that trains of internal solitary waves generated in the Strait of Gibraltar propa-gate mostly eastward into the Mediterranean Sea, while westward propa-gating wave trains can only be supported by a seasonal thermocline. 1
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Internal Waves Generated in the Straits of Gibraltar and Messina: Observations from Space
2015Co-Authors: Werner Alpers, Angelo RubinoAbstract:Abstract. The Straits of Gibraltar and Messina are areas where strong in-ternal solitary waves are generated by the interaction of tidal currents with shallow underwater ridges located within the straits. Remote sensing tech-niques and numerical simulations have been very instrumental in studying the generation and propagation of internal solitary waves in these sea ar-eas. It was a synthetic aperture radar (SAR) image acquired by the Ameri-can SEASAT Satellite in 1978 that first revealed that long internal waves are generated in the Strait of Messina. Furthermore, SAR images acquired by the European Remote Sensing Satellite ERS-1 and ERS-2 have revealed that trains of internal solitary waves generated in the Strait of Gibraltar propagate mostly eastward into the Mediterranean Sea, while westward propagating wave trains can only be supported by a seasonal thermocline.
Wang Nai-yu - One of the best experts on this subject based on the ideXlab platform.
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Sea surface temperature estimation using active and passive microwave remote sensing.
1998Co-Authors: Wang Nai-yuAbstract:Although sea surface temperature (SST) is often estimated from Satellite infrared observations, passive microwave techniques have the advantage of being applicable in cloudy regions. The goal of this research is to combine active and passive microwave measurements to improve the accuracy of the SST retrievals. A non-linear iterative inversion method for the retrieval of surface wind (U) and sea surface temperature (SST) using space-borne microwave scatterometer and radiometer measurements is developed and applied to data collected by the SEASAT Satellite. This retrieval algorithm is physically based, using an integrated microwave model for normalized radar cross section ($\sigma\sb0)$ and surface emissivity and a nonlinear least squares estimation technique. The $\sigma\sb0$ model is empirical, based on a SEASAT data set; While the emissivity model is physically-based. In the emissivity model the microwave reflectance R is estimated using the ocean wave spectrum of Bjerkaas and Reidel and a bistatic two-scale scattering model, and the microwave emissivity e is calculated as $e=1-R$ where R is microwave reflectivity. The validity of this active and passive microwave algorithm is evaluated for the case of an eastern pacific test area employing 14.6 GHz SEASAT scatterometer (SASS) and 6.6 GHz V-pol radiometer (SMMR) data. The results show that SST can be reliably estimated from SEASAT SASS/SMMR measurements for an open ocean area. Two sets of SMMR cells were analyzed. The averaged test-site correlation coefficient between the reference SST (measured by ships) and the SEASAT-based estimates of SST is 0.8916 and the corresponding standard errors are smaller than 0.7$\sp\circ$C. These results suggest that a physically based SST retrieval scheme can be useful in improving the accuracy of SST measurements made with passive microwave remote sensing.Ph.D.Applied SciencesEarth SciencesElectrical engineeringOcean engineeringPhysics, Atmospheric SciencePure SciencesRemote sensingUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/131567/2/9910018.pd
Werner Alpers - One of the best experts on this subject based on the ideXlab platform.
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Internal Waves Generated in the Straits of Gibraltar and Messina: Observations from Space
2015Co-Authors: Werner Alpers, Peter Brandt, Angelo RubinoAbstract:Abstract. The Straits of Gibraltar and Messina are areas where strong in-ternal solitary waves are generated by the interaction of tidal currents with shallow underwater ridges located within the straits. Remote sensing tech-niques and numerical simulations have been instrumental in studying the generation and propagation of internal solitary waves in these sea areas. It was a Synthetic Aperture Radar (SAR) image acquired by the American SEASAT Satellite in 1978 that first revealed that long internal waves are gen-erated in the Strait of Messina. Furthermore, SAR images acquired by the European Remote Sensing Satellite ERS-1 and ERS-2 have revealed that trains of internal solitary waves generated in the Strait of Gibraltar propa-gate mostly eastward into the Mediterranean Sea, while westward propa-gating wave trains can only be supported by a seasonal thermocline. 1
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Internal Waves Generated in the Straits of Gibraltar and Messina: Observations from Space
2015Co-Authors: Werner Alpers, Angelo RubinoAbstract:Abstract. The Straits of Gibraltar and Messina are areas where strong in-ternal solitary waves are generated by the interaction of tidal currents with shallow underwater ridges located within the straits. Remote sensing tech-niques and numerical simulations have been very instrumental in studying the generation and propagation of internal solitary waves in these sea ar-eas. It was a synthetic aperture radar (SAR) image acquired by the Ameri-can SEASAT Satellite in 1978 that first revealed that long internal waves are generated in the Strait of Messina. Furthermore, SAR images acquired by the European Remote Sensing Satellite ERS-1 and ERS-2 have revealed that trains of internal solitary waves generated in the Strait of Gibraltar propagate mostly eastward into the Mediterranean Sea, while westward propagating wave trains can only be supported by a seasonal thermocline.
Comiso, Josefino C. - One of the best experts on this subject based on the ideXlab platform.
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Satellite Observation Systems for Polar Climate Change Studies
2012Co-Authors: Comiso, Josefino C.Abstract:The key observational tools for detecting large scale changes of various parameters in the polar regions have been Satellite sensors. The sensors include passive and active Satellite systems in the visible, infrared and microwave frequencies. The monitoring started with Tiros and Nimbus research Satellites series in the 1970s but during the period, not much data was stored digitally because of limitations and cost of the needed storage systems. Continuous global data came about starting with the launch of ocean color, passive microwave, and thermal infrared sensors on board Nimbus-7 and Synthetic Aperture Radar, Radar Altimeter and Scatterometer on board SEASAT Satellite both launched in 1978. The Nimbus-7 lasted longer than expected and provided about 9 years of useful data while SEASAT quit working after 3 months but provided very useful data that became the baseline for follow-up systems with similar capabilities. Over the years, many new sensors were launched, some from Japan Aeronautics and Space Agency (JAXA), some from the European Space Agency (ESA) and more recently, from RuSSia, China, Korea, Canada and India. For polar studies, among the most useful sensors has been the passive microwave sensor which provides day/night and almost all weather observation of the surface. The sensor provide sea surface temperature, precipitation, wind, water vapor and sea ice concentration data that have been very useful in monitoring the climate of the region. More than 30 years of such data are now available, starting with the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7, the Special Scanning Microwave/Imager (SSM/I) on board a Defense Meteorological Satellite Program (DMSP) and the Advanced Microwave Scanning Radiometer on board the EOS/ Aqua Satellite. The techniques that have been developed to derive geophysical parameters from data provided by these and other sensors and associated instrumental and algorithm errors and validation techniques will be discussed. An important issue is the organization and storage of hundreds of terabytes of data collected by even just a few of these Satellite sensors. Advances in mass storage and computer technology have made it possible to overcome many of the collection and archival problems and the availability of comprehensive Satellite data sets put together by NASA's Earth Observing System project will be discussed
Kniffen S. - One of the best experts on this subject based on the ideXlab platform.
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Linear retrieval, validation and mapping of the sea surface temperature over western mid-latitude North Pacific using SEASAT SMMR data
'Informa UK Limited', 1991Co-Authors: Pandey P. C., Kniffen S.Abstract:The Scanning Multichannel Microwave Radiometer (SMMR) aboard the SEASAT Satellite measured emitted radiation in both horizontal and vertical polarizations at microwave frequencies of 6.6, 1069, 18.0, 21.0 and 37.0 GHz. Retrieval algorithms, for sea surface temperature (SST) determination, from subsets of one to three SMMR channels, are obtained by a two-step statistical technique. The technique first selects the best subsets of a given size defined by an R2 criterion (coefficient of determination), of a given size by the application of an efficient leaps and bounds technique on a statistical data base. It then performs a regression analysis on the selected subsets. The statistical data base employed a large (600) set of seasonally and geographically diverse atmospheric and surface parameters for radiative transfer calculations. The results of the study of one to three-channel subset retrieval algorithms indicate the possibility of using 6.6 V, 6.6 H and 18 V channels for SST determinatidn from SEASAT-SMMR data. A comparison of SMMR-SST derived from three channels mentioned above and expendable bathythermograph (XBT) measurements over the North Pacific provided an r.m.s. difference of 1.4 K which is comparable to the accuracy obtained from a five-channel subset (6 6 V, 6-6 H, 10-69 H, 180V, 21 OH) retrieval algorithm. The retrieval technique has the ability to recognize severe noise in brightness temperature measurements which may lead to unacceptable parameter retrieval. This may be achieved by setting up a quality control criteria either using different subsets of the same size or of different sizes. The three-channel retrieval compares within 1.2 K with Chester's algorithm, which is being used at the Jet Propulsion Laboratory for geophysical processing. Ten-day and monthly average SMMR-SST contour maps are produced using three-channel retrieval for the period 7 July-6 August 1978 over the western North Pacific, 20°-50° N, 140°-180° E. These contour maps are compared against similar maps obtained from Chester's algorithm and ship's observations. All the SMMR-SST maps show the major climatological features and are in reasonable agreement with ship's SST maps