该文基于美国国家浮标资料中心(National Data Buoy Center,NDBC)浮标观测数据对哨兵一号搭载的合成孔径雷达(synthetic aperture radar,SAR)反演风速数据进行精度分析,并利用BP神经网络(back propagation neural network)对SAR反演风...该文基于美国国家浮标资料中心(National Data Buoy Center,NDBC)浮标观测数据对哨兵一号搭载的合成孔径雷达(synthetic aperture radar,SAR)反演风速数据进行精度分析,并利用BP神经网络(back propagation neural network)对SAR反演风速的偏差进行校正;同时针对环境要素、BP神经网络训练输入的样本量以及神经网络结构参数设计了敏感性试验;最后将SAR标量风场数据转换为用u、v矢量表示的风场数据,并对u向风和v向风分别进行了精度分析和校正。实验结果表明:SAR反演风速相较于浮标观测数据出现了低估现象;经过BP神经网络校正后,SAR反演风速数据的精度得到了改善,风速的平均偏差绝对值从0.78 m s下降到0.04 m s,均方根误差从1.98 m s下降到了1.77 m s;敏感性试验表明输入质量较差的环境要素数据时BP神经网络的校正效果有所下降,而增加训练集样本量能改善校正效果;将标量风场数据转换为u、v矢量风场数据后的校正结果也显示BP神经网络具有较好的校正效果。展开更多
利用美国国家浮标数据中心NDBC和热带大气海洋计划TAO浮标的海表面温度数据,对Wind Sat 2004年—2013年近10年的海表面温度产品进行了验证。结果表明,在美国沿岸海域,Wind Sat反演得到的海表面温度的平均偏差为0.10°C,标准偏差为0....利用美国国家浮标数据中心NDBC和热带大气海洋计划TAO浮标的海表面温度数据,对Wind Sat 2004年—2013年近10年的海表面温度产品进行了验证。结果表明,在美国沿岸海域,Wind Sat反演得到的海表面温度的平均偏差为0.10°C,标准偏差为0.59°C;在近赤道太平洋海域,反演得到的海表面温度的平均偏差为–0.15°C,标准偏差为0.33°C。Wind Sat海表面温度在夏季相对浮标实测值有正偏差增大和负偏差缩小的趋势,在美国东海岸以及墨西哥湾区域部分站点反演得到的海表面温度的标准偏差较大,其标准偏差超过1°C。在5–10 m/s风速段,Wind Sat海表面温度反演效果比较理想,平均偏差和标准偏差相对恒定。当风速大于12 m/s时,Wind Sat海表面温度反演的不确定性明显增加。与AMSR-E月平均海表面温度产品对比发现,夏季,Wind Sat SST较AMSRE偏低;冬季,Wind Sat SST较AMSR-E偏高。展开更多
Significant wave height（SWH） can be computed from the returning waveform of radar altimeter, this parameter is only raw estimates if it does not calibrate. But accurate calibration is important for all applications,...Significant wave height（SWH） can be computed from the returning waveform of radar altimeter, this parameter is only raw estimates if it does not calibrate. But accurate calibration is important for all applications, especially for climate studies. HY-2a altimeter has been operational since April 2012 and its products are available to the scientific community. In this work, SWH data from HY-2A altimeters are calibrated against in situ buoy data from the National Data Buoy Center（NDBC）, Distinguished from previous calibration studies which generally regarded buoy data as ＂truth＂, the work of calibration for HY-2A altimeter wave data against in situ buoys was applied a more sophisticated statistical technique-the total least squares（TLS） method which can take into account errors in both variables. We present calibration results for HY-2A radar altimeter measurement of wave height against NDBC buoys. In addition, cross-calibration for HY-2A and Jason-2 wave data are talked over and the result is given.展开更多
Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy obser...Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy observations over a 10-year period(i.e.,2009–2019),colocated wind and wave energy resources are estimated.Although buoy records are imper-fect,results show that the inner Caribbean Sea(CS)under the infuence of the Caribbean low-level jet has the highest wind energy resource at~1500 W/m^(2),followed by the outer CS at~600 W/m^(2) and Atlantic Ocean(AO)at~550–600 W/m^(2) at a 100 m height.Wave energy was most abundant in the AO at 14 kW/m,followed by the inner CS at 13 kW/m and outer CS at 5 kW/m.The average and dominant wave energies can reach a maximum of 10 and 14 kW/m,respectively.Asymmetry between wind and wave energy resources is observed in the AO,where wave energy is higher than the low wind speed/energy would suggest.Swell is responsible for this discrepancy;thus,it must be considered not only for wave energy extraction but also for wind turbine fatigue,stability,and power extraction efciency.展开更多
文摘该文基于美国国家浮标资料中心(National Data Buoy Center,NDBC)浮标观测数据对哨兵一号搭载的合成孔径雷达(synthetic aperture radar,SAR)反演风速数据进行精度分析,并利用BP神经网络(back propagation neural network)对SAR反演风速的偏差进行校正;同时针对环境要素、BP神经网络训练输入的样本量以及神经网络结构参数设计了敏感性试验;最后将SAR标量风场数据转换为用u、v矢量表示的风场数据,并对u向风和v向风分别进行了精度分析和校正。实验结果表明:SAR反演风速相较于浮标观测数据出现了低估现象;经过BP神经网络校正后,SAR反演风速数据的精度得到了改善,风速的平均偏差绝对值从0.78 m s下降到0.04 m s,均方根误差从1.98 m s下降到了1.77 m s;敏感性试验表明输入质量较差的环境要素数据时BP神经网络的校正效果有所下降,而增加训练集样本量能改善校正效果;将标量风场数据转换为u、v矢量风场数据后的校正结果也显示BP神经网络具有较好的校正效果。
文摘利用美国国家浮标数据中心NDBC和热带大气海洋计划TAO浮标的海表面温度数据,对Wind Sat 2004年—2013年近10年的海表面温度产品进行了验证。结果表明,在美国沿岸海域,Wind Sat反演得到的海表面温度的平均偏差为0.10°C,标准偏差为0.59°C;在近赤道太平洋海域,反演得到的海表面温度的平均偏差为–0.15°C,标准偏差为0.33°C。Wind Sat海表面温度在夏季相对浮标实测值有正偏差增大和负偏差缩小的趋势,在美国东海岸以及墨西哥湾区域部分站点反演得到的海表面温度的标准偏差较大,其标准偏差超过1°C。在5–10 m/s风速段,Wind Sat海表面温度反演效果比较理想,平均偏差和标准偏差相对恒定。当风速大于12 m/s时,Wind Sat海表面温度反演的不确定性明显增加。与AMSR-E月平均海表面温度产品对比发现,夏季,Wind Sat SST较AMSRE偏低;冬季,Wind Sat SST较AMSR-E偏高。
基金The Marine Public Welfare Project of China under contract No.201305032
文摘Significant wave height（SWH） can be computed from the returning waveform of radar altimeter, this parameter is only raw estimates if it does not calibrate. But accurate calibration is important for all applications, especially for climate studies. HY-2a altimeter has been operational since April 2012 and its products are available to the scientific community. In this work, SWH data from HY-2A altimeters are calibrated against in situ buoy data from the National Data Buoy Center（NDBC）, Distinguished from previous calibration studies which generally regarded buoy data as ＂truth＂, the work of calibration for HY-2A altimeter wave data against in situ buoys was applied a more sophisticated statistical technique-the total least squares（TLS） method which can take into account errors in both variables. We present calibration results for HY-2A radar altimeter measurement of wave height against NDBC buoys. In addition, cross-calibration for HY-2A and Jason-2 wave data are talked over and the result is given.
文摘Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy observations over a 10-year period(i.e.,2009–2019),colocated wind and wave energy resources are estimated.Although buoy records are imper-fect,results show that the inner Caribbean Sea(CS)under the infuence of the Caribbean low-level jet has the highest wind energy resource at~1500 W/m^(2),followed by the outer CS at~600 W/m^(2) and Atlantic Ocean(AO)at~550–600 W/m^(2) at a 100 m height.Wave energy was most abundant in the AO at 14 kW/m,followed by the inner CS at 13 kW/m and outer CS at 5 kW/m.The average and dominant wave energies can reach a maximum of 10 and 14 kW/m,respectively.Asymmetry between wind and wave energy resources is observed in the AO,where wave energy is higher than the low wind speed/energy would suggest.Swell is responsible for this discrepancy;thus,it must be considered not only for wave energy extraction but also for wind turbine fatigue,stability,and power extraction efciency.
