- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Improving Wind Forcing with Scatterometer Observations for Operational Storm Surge Forecasting in the Adriatic Sea
摘要： Reliable storm surge predictions rely on accurate atmospheric model simulations, especially of the sea surface pressure and wind vector. The Adriatic Sea is among the regional seas of the Mediterranean basin experiencing the highest tidal excursions, particularly in its northern side, the Gulf of Venice, where storm surge predictions are therefore of great importance. Unfortunately, sea surface wind forecasts in the Adriatic Sea are known to be underestimated. A numerical method aiming at reducing the bias between scatterometer wind observations and atmospheric model winds, has been developed. The method is called “wind bias mitigation” and uses the scatterometer observations to reduce the bias between scatterometer observations and the modeled sea surface wind, in this case that supplied by the European Centre for Medium-Range Weather Forecasts (ECMWF) global atmospheric model. We have compared four mathematical approaches to this method, for a total of eight different formulations of the multiplicative factor ?ws which compensates the model wind underestimation, thus decreasing the bias between scatterometer and model. Four datasets are used for the assessment of the eight different bias mitigation methods: a collection of 29 storm surge events (SEVs) cases in the years 2004-2014, a collection of 48 SEVs in the years 2013-2016, a collection of 364 cases of random sea level conditions in the same period, and a collection of the seven SEVs in 2012-2016 that were worst predicted. The statistical analysis shows that the bias mitigation procedures supplies a mean wind speed more accurate than the standard forecast, when compared with scatterometer observations, in more than 70% of the analyzed cases.
关键词： Sea surface wind,Atmospheric model,Forecasting,Adriatic Sea,Scatterometer,Storm surge
更新于2025-09-23 15:21:21
-
Comparison of sea surface wind field measured by HY-2A scatterometer and WindSat in global oceans
摘要： In this study, we present a comprehensive comparison of the sea surface wind field measured by scatterometer (Ku-band scatterometer) aboard the Chinese HY-2A satellite and the full-polarimetric radiometer WindSat aboard the Coriolis satellite. The two datasets cover a four-year period from October 2011 to September 2015 in the global oceans. For the sea surface wind speed, the statistical comparison indicates good agreement between the HY-2A scatterometer and WindSat with a bias of nearly 0 m/s and a root mean square error (RMSE) of 1.13 m/s. For the sea surface wind direction, a bias of 1.41° and an RMSE of 20.39° were achieved after excluding the data collocated with opposing directions. Furthermore, discrepancies in sea surface wind speed measured by the two sensors in the global oceans were investigated. It is found that the larger differences mainly appear in the westerlies in the both hemispheres. Both the bias and RMSE show latitude dependence, i.e., they have significant latitudinal fluctuations.
关键词： global comparisons,HY-2A scatterometer,sea surface wind field,polarimetric radiometer WindSat
更新于2025-09-23 15:21:21
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Ocean Surface Currents and Winds Using Dopplerscatt
摘要： Doppler Scatt is a Ka-band pencil-beam Doppler scatterometer developed under NASA’s ESTO Instrument Incubator Program (IIP) to serve as a demonstrator for future spaceborne instruments to measure ocean surface currents and winds simultaneously. We review the capabilities of the DopplerScatt instrument, and present results from multiple airborne campaigns. One of our primary results will be the development of Ka-band Geophysical Model Functions (GMFs) to translate backscatter and Doppler measurements into surface winds and currents.
关键词： scatterometer,Doppler,Ocean currents,ocean winds,radar
更新于2025-09-10 09:29:36
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Performances of the Rotating Fanbeam Scatterometer on Cfosat
摘要： The Ku-band rotating fan-beam scatterometer (RFSCAT) onboard the China-France Oceanography Satellite (CFOSAT) is dedicated to the measurement of sea surface wind vectors. The flight model of RFSCAT has been assembled and tested, and the data processing algorithms have been developed. This paper provides an overview of the design and characteristics of RFSCAT instrument, and then a prelaunch analysis is carried out to estimate the scatterometer backscatter and wind accuracy. The overall study includes two parts: first, a forward model is developed to simulate the ocean backscatter signals under certain wind conditions; second, a wind inversion processor is used to retrieve sea surface wind vectors from the outputs of the forward model. Simulations show that the backscatter accuracy and the retrieved wind quality of RFSCAT are quite promising and meet the scientific requirements of the mission.
关键词： Scatterometer,simulation,quality control,wind
更新于2025-09-10 09:29:36
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Wind Field Retrieving Under Rainy Conditions Based on Support Vector Machine for Combined Active/Passive Observations of HY-2A
摘要： Wind fields over ocean surface can be effectively retrieved by scatterometer measurements with GMFs (geophysical model functions) relating them and observing geometry with wind speeds. However, existed GMFs are not suitable for rainy conditions which require extra information for rain induced factors in observations that vary with rain conditions. The combined observations of scatterometer and radiometer are suitable for the problem. In this paper, this was realized by the method based on SVM (support vector machine) with kernel function established in this paper considering the form of existed GMFs. Experiments had been conducted over HY-2A scatterometer (HSCAT) and radiometer (HRAD) who give observations at almost the same time and operation frequencies suitable for this problem. The training progress was achieved by taken Windsat wind fields as true values. The method had been verified by comparison made between the wind fields retrieved with that of Buoy data. Discussion were made for further researches exploring the underlying physical progress of the SVM established.
关键词： HY-2A,scatterometer,radiometer,wind field,support vector machine,kernel function
更新于2025-09-10 09:29:36
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A Modified Scattering Model of Row Wheat at X-Band
摘要： Cereal crops, contrary to natural vegetation, have the different characteristics for their regular planting. Further, the random assumption of the radiative transfer theory is not suitable for cereal canopy. The paper aimed to present a modified scattering model of row wheat at X-band (center frequency 3.2GHz). The modified scattering model considered both the surface scattering of soil and the volume scattering of wheat canopy. In different wheat growth stage, the weights of the two kinds of scattering phenomenon were set up based on an empirical growth model because of their visible area. A series of data including wheat growth parameters and backscatter coefficients, related to the interaction, were collected for the analyses of the model. The research results showed the model could better reflect the scattering phenomenon of regulate planting, which is helpful to agriculture remote sensing fields.
关键词： scatterometer,vegetation,soil,Modeling,backscatter
更新于2025-09-10 09:29:36
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - The Simulation of Ocean Surface Wind Measured by Polarimetric Scatterometer
摘要： Ocean surface wind field is a very important marine dynamic parameter in marine environment forecasting and climatological studies. Spaceborne scatterometer is one of the most efficient remote sensors than can provide global ocean surface wind measurement. Polarimetric scatterometer (PolScat) simultaneously measures co-polarized and cross-polarized backscattering coefficient and the correlation coefficient of the co- and cross-polarized component of radar echoes which can significantly improve the performance of the sea surface wind field measurements. In this paper, we derive the error model of correlation scattering coefficient from radar echo signals. The effect of antenna polaxis deflection on correlation scattering coefficient error is analyzed. Moreover, an “end-to-end” system simulation model of PolScat is established. A modified Maximum Likelihood Estimation (MLE) is used for ocean surface wind field inversion. Both the co-polarized backscattering coefficient and correlation scattering coefficient are included in the objective function of MLE. The simulation results show that PolScat can effectively reduce the probability of ambiguous solutions. The wind speed and wind direction inversion accuracy of PolScat is better than 1m/s and 15° respectively.
关键词： inversion accuracy,system simulation,ocean surface wind vector,Polarimetric scatterometer
更新于2025-09-10 09:29:36
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Broadband Full Polarimetric Scatterometry for Monitoring Soil Moisture and Vegetation Properties Over a Tibetan Meadow
摘要： A scatterometer is installed on a meadow over the Tibetan Plateau in August 2017 to measure the full polarimetric backscattering coefficient ??0 over a wide frequency range (1 - 10 GHz) year-round. In this paper we describe the setup of scatterometer as well as the activities undertaken to test the reliability of the system. The measured radar cross section of a dihedral reflector matches the theoretical model for 3 – 10 GHz after the calibration. The temperature-induced systematic error in the radar return will be accounted for by using the antenna cross coupling as a reference. For the retrieval of ?0 the frequency-dependent antenna radiation pattern and the site geometry are accounted for. Fading will be dealt with by using frequency agility techniques.
关键词： Radar cross section calibration,Time-domain gating,Tibetan Plateau,Broadband,Scatterometer
更新于2025-09-10 09:29:36
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - CFOSAT Mission: Using of Swim Measurements for Improving Scat Wind Vector Retrieval
摘要： CFOSAT (the China France Oceanography Satellite) is the joint mission from the Chinese and French Space Agencies to jointly perform global ocean surface wind and sea state observation and monitoring. The satellite will carry two Ku-band radars: the wave scatterometer (SWIM) and the wind scatterometer (SCAT). Such a unique configuration provides multi-look and multi-angle observations to reconstruct key parameters of local sea surface conditions: the directional wave spectrum and the determination of the sea surface wind speed and direction. From unique collocated wave and wind measurements, each single instrument observation by its own can benefit from the other one. As often discussed, radar re-turns, at the same location but for different angles of observations, will possibly exhibit different sensitivity with regard to various sea surface parameters, i.e. near-surface wind speed and direction, significant wave height, sea state degree of development and/or local swell wave spectrum characteristics. This often results in radar signal dispersion which limits the precision of the retrieval algorithms from radar remote sensing measurements. Accordingly, the potential to benefit from additional information from a co-located second instrument could be strongly useful in the correction of such factors. The present work considers the possibility of using the near-nadir SWIM measurements to improve the wind estimates from the scatterometer inversion algorithm. Preliminary estimates and simulations confirm that some types of errors, e.g. due to SCAT antenna geometry and configuration, can largely be reduced. As well, additional improvement can be expected for the measurements under low-wind and rapidly changing sea conditions.
关键词： ocean remote sensing,CFOSAT,surface ocean wind scatterometer
更新于2025-09-09 09:28:46
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Wind Field Retrieving for SCAT Onboard CFOSAT Based on PCA Method
摘要： The scatterometer (SCAT) onboard China France Oceanography Satellite (CFOSAT) will be the first scanning scatterometer with rotating fan-beams. Wind retrieving methods for existed scatterometers, which are with rotating pencil beams or fixed fan beams, are needed to be modified considering efficiency in information extraction from the numerous observations acquired in this working mode. This was achieved in the research of this paper by applying Principle Component Analysis (PCA) method. Firstly, vectors for applying PCA are composed in two different ways for analysis of the effectiveness of information extraction for the SCAT data and for wind retrieving respectively. Then the description of simulated SCAT data considering observing geometry and SCAT working mode was given. Then experiments of PCA based wind retrieving method was carried out with conclusion that it was effective in information extraction for preparing data sets for wind retrieving. Finally, further research has been discussed.
关键词： wind retrieval,principle component analysis (PCA),China-France Oceanography Satellite (CFOSAT),Scatterometer (SCAT),simulated data
更新于2025-09-09 09:28:46