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The Hurricane Imaging Radiometer, HIRad, is a new instrument for making wind and rain observations in hurricanes. It is being developed by NASA to give NOAA improved capability in forecasting hurricane intensity and track. HIRad is being designed to measure ocean surface wind speed up to greater than 70 m/sec. over a swath out to plusmn60 deg. Current surface emissivity models are not adequate for...
Seasonal and interannual variability of the spring bloom in the Gulf of Cadiz, western North Atlantic, has been investigated using remote sensing chlorophyll-a (chl-a) concentration between 1997 and 2007. Variability in both the timing and magnitude of the spring bloom in the basin has been evaluated according to physical properties in the water column such as mixed layer depth (MLD), sea surface...
To properly assess the impact of global climate change and plan for remediation, accurate regional climate models are necessary, functioning on 10 km size scales rather than the typical 100 km scales. Examples of 10 km size scale phenomena are coastal wind eddies at 10-40 km scales, studied over Monterey Bay,California by Archer,Ludwig et al. using shore and buoy anemometers and satellite images....
The Cantarell Seep is the most significant natural seep discovered in the Southern Gulf of Mexico. The trajectory of the oil seep, driven by sea surface winds and ocean currents, can sometimes impinge on the environmentally sensitive Mexican coast. For this reason it is necessary for the implementation of slick impact models to determine and track oil slick behaviour on sea surface as an aid to contingency...
The measurement of peak winds in hurricanes is critical to forecasting intensity and direction prior to landfall. To date, the NOAA stepped frequency microwave radiometer, SFMR, is the best tool for providing this information. NASA is now developing the hurricane imaging radiometer, HIRad, which is a candidate follow-on instrument to improve on the SFMR. HIRad will use synthetic thinned array technology...
This study explores a national methodology for assessing the risk that peak wind gusts pose to Australian communities. This risk has been estimated for four cities across Australia, specifically; Perth, Cairns, Brisbane and the Gold Coast. Initially the return period regional wind speeds for three second peak gusts (estimation of the wind speeds that would be equaled or exceeded within a given time...
An angular-dependent split-window equation is proposed for determining the Sea Surface Temperature (SST) at any observation angle, including large viewing angles at the image edges of satellite sensors with wide swaths. The proposed equation takes into account the angular dependences of the atmospheric correction and also the emissivity correction. An explicit dependence on the SSE is considered in...
Spaceborne active sensors have been used for years to study the Earth's surface and atmosphere. The intent of this paper is to present the unique types of active remote sensors and their characteristics that apply to disaster management; and to present a status of current frequency spectrum use and needs of spaceborne active sensors, along with any issues or concerns.
Synthetic aperture radar (SAR) provides a promising method for offshore wind field estimation, particularly in the context of important for offshore wind farm development. This paper introduces an iterative maximum aposteriori probability (MAP) method for combining meteorological model output with synthetic aperture radar for offshore wind field estimation. The MAP approach is demonstrated for 40...
We present here the follow-up of a previously published work [1], where we described a wavelet based method to characterize the sea surface backscatter structures present in the SAR images. The method relies on the ability of the two- dimensional continuous wavelet technique to detect the spatial structure of the marine atmospheric boundary layer and to isolate wind-related cells and features. The...
Starting in 1991, the ERS-1 and (later) ERS-2 satellites have collected wavemode data over the global oceans whenever no image mode data acquisition was requested. Wave- mode data are full resolution SAR data covering small areas of size 5 km times 10 km every 200 km along the orbits thus forming a dataset giving information from all global oceans daily. In the scope of the WAVEATLAS ESA AO Project,...
This paper describes the experimental activities carried out during the international experiment CAPMOS'05, which was carried out on an off-shore platform in Katsiveli, Ukraine, in May-June 2005. During the experiment, the sea surface was continuously observed by synchronous active and passive microwave instruments, combined with contact and optical observations, in order to retrieve the wave parameters...
Recently satellite SAR techniques have become essential observation tools for various ocean phenomena such as wind, wave and current. The CMOD4 and CMOD-IFR2 models are used to calculate the magnitude of wind at SAR resolution with no directional information. Combination of the wave-SAR spectrum analysis and the inter-look cross-spectra techniques provides amplitude and direction of the ocean wave...
Using in situ observations, study is performed on a few related properties of wind raised sand grains during sandstorms in the Yanchi area of Ninxia in NW China, indicating that the critical wind responsible for sands lifting from 10 m level above surface is 5.0 m/s and the critical frictional velocity is 0.32 m/s, the maximal amount of sand transport is 12.42 kg m-1 based on the "scheme of maximum...
Currently the European satellites ERS-2 and ENVISAT are flying on the same orbit with a time separation of 30 minutes. In this presentation pairs of the respective synthetic aperture radar data are analyzed with respect to different atmospheric and oceanic processes. The presented results were obtained in the framework of the ESA AO project COTAR. The tandem configuration exists since the launch of...
The UPC lidar group is developing a Doppler wind lidar based on the "edge-technique". Such systems use the slope of a high resolution optical filter as frequency discriminator. A laboratory prototype, able to measure the speed of solid targets emitting continuous wave radiation and using a Fabry-Perot interferometer as optical filter, has been built. A tuning control has been included to...
Range unambiguous high duty cycle coherent lidars can be constructed based on frequency stepped pulse train modulation, even continuously emitting systems could be envisioned. Such systems are suitable for velocity sensing of dispersed targets, like the atmosphere, at fast acquisition rates. The lightwave synthesized frequency sweeper is a suitable generator yielding fast pulse repetition rates and...
This paper describes the simulation of the power- waveforms acquired in by a radar altimeter operating in SAR mode over ocean surfaces, including the effects of the radar transfer function and of the geophysical ocean parameters, namely the sea surface height( SSH), the sea surface wave height (SWH) and the surface wind speed (WS). The performances of the SAR mode with respect to the retrieval of...
Radar backscattered signals over the ocean are dampened in extremely high winds, which leads to a wind speed ambiguity problem during the process of wind retrieval from synthetic aperture radar (SAR). This problem was firstly studied by Shen et al. (2007), where we proposed a wind speed ambiguity removal scheme for the two wind speed solutions that may exist for any given normalized radar cross section...
The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) is responsible for the absolute calibration of the new Advanced scatterometer (ASCAT), onboard MetOp-A, which mainly relies on the use of transponders. An alternative calibration method, which uses scatterometer measurements over the ocean, is presented here. The method is based on the knowledge of the backscatter...
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