HY-2B卫星散射计海面风场产品质量分析 *
陈克海(1979—), 男, 广东省广州市人, 博士研究生, 主要从事测绘遥感和微波散射计研究。email: |
Copy editor: 林强
收稿日期: 2019-12-17
要求修回日期: 2020-05-12
网络出版日期: 2020-05-13
基金资助
国家自然科学基金项目(41876204)
国家自然科学基金项目(41476152)
广东工贸职业技术学院科研课题(2017-Z-5)
版权
Accuracy analysis of the retrieved wind from HY-2B scatterometer
Copy editor: LIN Qiang
Received date: 2019-12-17
Request revised date: 2020-05-12
Online published: 2020-05-13
Supported by
National Natural Science Foundation of China(41876204)
National Natural Science Foundation of China(41476152)
Scientific Project of Guangdong Polytechnic of Industry and Commerce(2017-Z-5)
Copyright
星载微波散射计是获取全球海面风场信息的主要手段, HY-2B卫星散射计的成功发射为全球海面风场数据获取的持续性提供了重要保障。本文利用欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasts, ECMWF)再分析风场数据、热带大气海洋观测计划(Tropical Atmosphere Ocean Array, TAO)和美国国家数据浮标中心(National Data Buoy Center, NDBC)浮标获取的海面风矢量实测数据, 对HY-2B散射计海面风场数据产品的质量进行统计分析。分析表明, HY-2B风场与ECMWF再分析风场对比, 在4~24m·s-1风速区间内, 风速和风向均方根误差(root mean square error, RMSE)分别为1.58m·s-1和15.34°; 与位于开阔海域的TAO浮标数据对比, 风速、风向RMSE分别为1.03m·s-1和14.98°, 可见HY-2B风场能较好地满足业务化应用的精度要求(风速优于2m·s-1, 风向优于20°)。与主要位于近海海域的NDBC浮标对比, HY-2B风场的风速、风向RMSE分别为1.60m·s-1和19.14°, 说明HY-2B散射计同时具备了对近海海域风场的良好观测能力。本文还发现HY-2B风场质量会随风速、地面交轨位置等变化, 为用户更好地使用HY-2B风场产品提供参考。
陈克海 , 解学通 , 张金兰 , 邹巨洪 , 张毅 . HY-2B卫星散射计海面风场产品质量分析 *[J]. 热带海洋学报, 2020 , 39(6) : 30 -40 . DOI: 10.11978/2019138
Spaceborne microwave scatterometer is the most efficient instrument to measure the global ocean surface wind. The successfully launched HY-2B scatterometer is an important guarantee to continue the measurement of global ocean surface wind. In this paper, we use the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis wind data, Tropical Atmosphere Ocean Array (TAO) and National Data Buoy Center (NDBC) buoy wind data to estimate the accuracy of the HY-2B retrieved wind. Our statistical results show that at speed range from 4 to 24 m·s-1, the retrieved wind speed root mean square error (RMSE) with respect to the ECMWF wind speed is 1.58 m·s-1, and the direction RMSE is 15.34°, while the speed and direction RMSEs with respect to the TAO buoys located in the open ocean are 1.06 m·s-1 and 15.98°, respectively. Thus, the retrieved wind well satisfies the operational precision requirement of the HY-2B scatterometer, that is, the speed and direction RMSEs should be better than 2 m·s-1 and 20.00°, respectively, for the open ocean. Moreover, the NDBC buoys are mainly located in immediate offshore areas, HY-2B wind speed and direction RMSEs are 1.60 m·s-1and 19.14°, respectively, which shows that HY-2B scatterometer has good ability to measure wind of offshore sea areas. We also reveal that the retrieved wind error varies with wind speed and cross track position of wind vector cell, which will provide the users with reference for the effective application of HY-2B wind product.
表1 HY-2B与ECMWF的风矢量偏差统计Tab. 1 Statistics of wind vector deviation of HY-2B vs ECMWF |
风速区间/( m·s-1 ) | HY-2B~ECMWF风速误差 | HY-2B~ECMWF风向误差 | ||||||
---|---|---|---|---|---|---|---|---|
偏差均值/(m·s-1) | 绝对偏差均值/( m·s-1) | 均方根误差/(m·s-1) | 绝对偏差小于2m·s-1的比例/% | 偏差均值 | 绝对偏差均值 | 均方根 误差 | 绝对偏差小于20°的比例/% | |
0~4 | 1.43 | 1.80 | 2.01 | 68.90 | 0.48° | 38.99° | 52.60° | 38.81 |
4~24 | 0.27 | 1.18 | 1.58 | 84.85 | 0.78° | 11.53° | 15.34° | 83.40 |
图3 HY-2B与ECMWF的风矢量偏差概率分布情况a. 风速绝对偏差累积概率; b. 风速绝对偏差小于2m·s-1的比例随风速的变化; c. 风向绝对偏差累计概率; d. 风向绝对偏差小于20°的比例随风速的变化 Fig. 3 Probability distribution of HY-2B vs ECMWF wind vector deviation: a) cumulative distribution of speed absolute deviation; b) ratio of speed absolute deviation within 2 m·s-1 varying with speed; c) cumulative distribution of direction absolute deviation; d) ratio of direction absolute deviation within 20° varying with speed |
表2 HY-2B与TAO浮标的风矢量偏差统计Tab. 2 Statistics of wind vector deviation of HY-2B vs TAO buoys |
风速区间 /(m·s-1) | 匹配数据数目 | 异常点数 目(比例/%) | HY-2B~TAO风速误差 | HY-2B~TAO风向误差 | ||||||
---|---|---|---|---|---|---|---|---|---|---|
偏差均值 /(m·s-1) | 绝对偏差均值/(m·s-1) | 均方根误差/(m·s-1) | 绝对偏差小 于2 m·s-1的比例/% | 偏差 均值 | 绝对偏 差均值 | 均方 根误差 | 绝对偏差小于20°的比例/% | |||
0~4 | 296 | 0 (0%) | 1.02 | 1.34 | 1.74 | 81.16 | -2.93° | 42.90° | 59.84° | 42.12 |
4~13* | 1613 | 35(2.22%) | 0.49 | 0.77 | 1.03 | 94.67 | 1.78° | 11.13° | 14.98° | 86.68 |
注: *TAO浮标位于赤道附近(纬度15°S—15°N), 赤道风速低, 这里TAO风速只统计到13m·s-1 |
表3 HY-2B与NDBC浮标的风矢量偏差统计Tab. 3 Statistics table of wind vector deviation of HY-2B vs NDBC buoys |
风速区间/( m·s-1) | 匹配数据数目 | 异常点数目 (比例) | HY-2B与NDBC的风速误差 | HY-2B与NDBC的风向误差 | ||||||
---|---|---|---|---|---|---|---|---|---|---|
偏差均值/(m·s-1) | 绝对偏差均值/(m·s-1) | 均方根误差/(m·s-1) | 绝对偏差小于2m·s-1的比例/% | 偏差 均值 | 绝对偏差均值 | 均方根误差 | 绝对偏差小于20°的比例/% | |||
0~4 | 308 | 0(0%) | 1.30 | 1.65 | 1.85 | 69.80 | 3.60° | 49.24° | 64.02° | 29.87 |
4~13* | 1442 | 24(1.70%) | 0.34 | 1.15 | 1.54 | 85.36 | 4.20° | 15.31° | 20.07° | 75.95 |
4~24 | 1772 | 31(1.79%) | 0.25 | 1.20 | 1.60 | 83.14 | 5.06° | 14.86° | 19.14° | 76.73 |
注: * 增加4~13m·s-1风速区间是为了与TAO浮标对比。 |
图6 HY-2B与浮标(TAO、NDBC)的风矢量散点图a. HY-2B与TAO的风速散点图; b. HY-2B与TAO的风向散点图; c. HY-2B与NDBC的风速散点图; d. HY-2B与NDBC的风向散点图 Fig. 6 Wind scatter plot of HY-2B vs buoy (TAO, NDBC ). a) speed scatter plot of HY-2B vs TAO; b) direction scatter plot of HY-2B vs TAO; c) speed scatter plot of HY-2B vs NDBC; d) direction scatter plot of HY-2B vs NDBC |
图7 HY-2B与浮标(TAO、NDBC)的风矢量偏差直方图a. HY-2B与TAO的风速偏差直方图; b. HY-2B与TAO的风向偏差直方图; c. HY-2B与NDBC的风速偏差直方图; d. HY-2B与NDBC的风向偏差直方图 Fig. 7 Wind deviation histogram of HY-2B vs buoys ( TAO, NDBC ): a) speed deviation histogram of HY-2B vs TAO; b) direction deviation histogram of HY-2B vs TAO; c) speed deviation histogram of HY-2B vs NDBC; d) direction deviation histogram of HY-2B vs NDBC |
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