温莎

Introduction

的WindSat偏振辐射计by the Naval Research Laboratory (NRL) Remote Sensing Division and the Naval Center for Space Technology for the U.S. Navy and the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Integrated Program Office (IPO). It was launched on January 6, 2003 aboard the Department of Defense Coriolis satellite. WindSat was meant to demonstrate the capabilities of a fully polarimetric radiometer to measure the ocean surface wind vector from space. Prior to launch, the only instrument capable of measuring ocean wind vectors were scatterometers (active microwave sensors). In addition to wind speed and direction, the instrument can also measure sea surface temperature, soil moisture, ice and snow characteristics, water vapor, cloud liquid water, and rain rate.

仪器描述

有关Windsat仪器的详细描述,请参阅P.Gaiser,“The WindSat Spaceborne Polarimetric Microwave Radiometer: Sensor Description and Early Orbit Performance“。温莎operates on the Coriolis satellite which is in a near-polar orbit. The local ascending node time is maintained at 6pm. This means the instrument passes over the equator at 6pm as it travels from south to north and at your location is measuring the surface near this time depending on your latitude.

Windsat辐射计很校准,包含SST检索所需的较低频率通道。辐射计在5个离散通道中运行:6.8,10.7,18.7,23.8和37.0 GHz。除了仅有双极化的6.8和23.8 GHz频道之外,所有都是完全偏振数。表1总结了通道详细信息。每个频率通道的进料沿扫描轨道轨道不同的电弧,因此接地入射角(EIA)对于每个频带不同。与先前的辐射仪不同,Windsat传感器在前向和尾扫描期间考虑观察。这使得地球的帆板几何形状与其他被动微波传感器的工作相比,地球视图的几何形状非常不同,并且明显更复杂。RSS Windsat产品是唯一使用前后看的DataSet可用的数据集。通过使用两个方向,我们获得更宽的条态和更复杂的静物几何,就像浏览图像中可见一样。

表1:WindSat信道、极化、地球入射角和信道分辨率总结。垂直方向的偏振光列为V,水平方向的偏振光列为H,+45度的偏振光列为P,左圆形的偏振光列为L,右圆形的偏振光列为R。
乐队[GHz] 极化 普通EIA

[Deg]

空间分辨率
(3 dB占地面积大小)

[km x km]

6.8 V, H 53.8 39 x 71
10.7 五、 H、P、M、L、R 50.1 25 x 38
18.7 五、 H、P、M、L、R 55.6 16 x 27.
23.8 V, H 53.2 20 x 30英寸
37 五、 H、P、M、L、R 53.2 8 x 13.

After a post-launch checkout period, the WindSat data started on February 5, 2003. With some short periods of non-operation, the instrument continues to operate in the present time. Data gaps are generally due to missing data upstream from our processing facility, such as the instrument being turned off. Occasionally, there are delays in obtaining and/or processing recently recorded data. If the data are not present after several weeks, it is unlikely that the missing data will become available. We keep a record of missing data:List of WindSat gaps

数据处理

We obtain WindSat antenna temperature data from NRL and NOAA. By using both these sources, we aim to provide scientists with as complete a set of data as possbile for their research. Using a consistent processing scheme and a robust radiative transfer model, we intercalibrate the WindSat data with the other microwave radiometers, obtain brightness temperatures, and then produce our ocean measurement products for distribution. The WindSat Ocean Products include Sea Surface Temperature (SST); a variety of Surface Wind Speeds and Directions; Atmospheric Water Vapor; Cloud Liquid Water; and Rain Rates.

万博体育app网页注册遥感系统分两个阶段对WindSat仪器数据进行详细处理。第一阶段产生一个近实时(NRT)产品(在文件名中用“rt”标识),我们会尽快提供该产品。这通常是在数据被记录后的3小时内,除了接收或处理数据的偶尔延迟。尽管NRT产品适合于许多及时使用,而且差异可能看起来很细微,但NRT产品并不具有归档/研究质量。它们将在一周内被删除,不应存档。万博网址是什么

当我们收到NCEP FNL分析时,将处理“最终”数据(由文件名中的“v7.0.1”标识)。NCEP风向对于检索更精确的SST和风速特别有用。最终的“v7.0.1”产品将继续积累新的条子(半轨道),直到地图已满,一般在7天内。偶尔,数据会在更长时间延迟之后可用,此类数据将被添加到最终的“V7.0.1”产品中。因此,最终指的是SWATH处理的类型,并且并不意味着数据文件最终确定(如在,永远不会改变)。当我们从我们的来源获得数据时,将添加新可用数据条款。我们可以添加到最终的“v7.0.1”产品中。

Several steps are involved in the WindSat data processing:

  1. US Naval Research Lab provides RSS with Level-1A antenna temperatures also known as Temperature Data Records (TDR). We process the data into Level-2A calibrated top of the atmosphere brightness temperatures (TBs). The most important issues of this calibration procedure are discussed in theGMI ATBD
  2. 然后将大气Tb的顶部最佳地插入固定的0.125度的地球网格,从中检索各种海洋测量。万博吧manbet客户端2.0然后通过简单的BIN重新采样为0.25°GID来创建我们的FTP站点上的产品。虽然每个产品都放在0.25°栅格上,有效解决数据的变化。下表概述了Windsat海洋测量的顺序,它们出现在二进制文件中,并列出了每个产品的有效空间分辨率。万博吧manbet客户端2.0

表2:按RSS二进制数据文件提供的顺序进行的Wmanbet客户端2.0万博吧indSat海洋测量。每个测量的有效空间分辨率从数据映射到的0.25度网格变化。通道极化列为V表示垂直,H表示水平,P表示+45度,L表示左圆形,R表示右圆形。
Ocean Measurement 缩写 有效的空间
分辨率[km x km]
Channels Required
for Retrieval
时间 时间 N / A. N / A.
Sea surface temperature 不锈钢 39 x 71 6.8 VH,10.7 VH,18.7 VH,23.8 VH,37.0 VH
使用低频通道十米风速 wspd_lf. 25 x 38 10.7 VH,18.7 VH,23.8 VH,37.0 VH
Ten-meter wind speed using medium frequency channels wspd_mf. 16 x 27. 18.7 VH,23.8 VH,37.0 VH
柱状大气水蒸气 水蒸气 16 x 27. 18.7 VH,23.8 VH,37.0 VH
柱状云液体含水量 CLOUD 16 x 27. 18.7 VH,23.8 VH,37.0 VH
Rain rate RAIN 8 x 13. 18.7 VH,23.8 VH,37.0 VH
All-weather 10-meter wind speed 华盛顿特区 25 x 38 no rain

39 x 71 in rain

6.8甚高频、10.7甚高频、18.7甚高频、23.8甚高频、37.0甚高频
Ten-meter wind direction (relative to north) WDIR. 25 x 38 10.7VHPMLR, 18.7 VHPMLR, 23.8 VH, 37.0 VHPMLR

If any of the required channels for a geophysical parameter are not available, then the retrieval is not completed.例如,这可能导致给定位置的蒸气检索,但在同一位置中没有WSPD_LF或SST。SST检索通常缺少条件中心,因为没有6.8 GHz观察。风向在条形边缘不可用,因为没有Polarimetric观察。这种“缺失数据”外观与其他RSS辐射计产品不同。

RSS Windsat数据产品

目前版本的遥感系统WindSat数据产品是v7万博体育app网页注册.0.1,WindSat数据于2013年8月重新处理,以消除2008年1月后影响风速和风向的轻微处理错误。产品文件中的所有其他数据与早期版本7相同。我们在一个文件中为每天、3天、每周和每月提供一套数据。数据集包含上面表2中列出的测量值。万博吧manbet客户端2.0

温莎data products include the standard set of measurements (sea surface temperature, wind speed, water vapor, cloud liquid water, and rain rate) and differ from other RSS radiometer products in that we can include additional measurements:

  1. WDIR.: Because of its polarimetric channels, WindSat can measure surface wind direction. WDIR is only provided if the wind speed exceeds 3 m/s and the rain rate is below 15 mm/hr. The wind directions in our product are inoceanographic convention
  2. WSPD_AW:我们在提高雨水中提高风速检索方面取得了重大进展。看风-Vector Retrievals Under Rain With Passive Satellite Microwave Radiometers,以获取有关所用算法的更多详细信息。如果6.8ghz信道与所有其他垂直和水平极化信道一起可用,我们可以在无雨和多雨大气中反演WindSat表面风速。我们结合了各种算法,包括在所有降雨条件下工作的全球风速通过降雨算法和专门为热带气旋训练的H-wind算法。在我们的二进制文件中提供的最终全天候风速WSPD\u AW是在非降雨条件下获得的标准风速WSPD\u LF、通过降雨的全球风速和H-wind导出的风速之间的平滑混合。

In addition to the all-weather wind speeds, we produce two standard rain-free radiometer wind products: WSPD_LF (low-frequency) and WSPD_MF (medium frequency). The first, WSPD_LF is created using the frequency channels at 10.7 GHz and above (see Table 1) and is most similar to the AMSR-E wind. The second, WSPD_MF, uses frequency channels at 18.7 GHz and above and is most similar to the SSM/I wind. Each wind product has distinct advantages. The WSPD_LF is less affected by the atmosphere and rain, but is affected by 10.7 GHz RFI and sun glitter effects. The WSPD_MF has a higher effective spatial resolution, is less affected by ice and land contamination, and only slightly affected by sun glitter effects, and RFI. The WSPD_MF are a little noisier than the WSPD_LF.

网格二进制数据文件

我们每天和时间平均(3天,每周和每月)二进制数据文件产生Windsat。文件不包含任何标题或元数据,并且是一组简单的单字节阵列,如下所述。由于数据存储为单个字节,因此在机器之间传输时没有字节交换是必要的。

根据观察日期组织网格数据文件。所有日期和时间都是协调的世界时(UTC),也称为格林威治意平时(GMT),Zulu Time(Z),世界时(UT)和世界时间。数据产品包括每日和时间平均测量,如下所示:万博吧manbet客户端2.0

日常 轨道数据映射到0.25度网格
根据升序和降序通行证分为2套地图
when adjacent passes overlap at high latitudes and daily "seam", earlier data is chosen.(见下面的注意)
3天 截止归档日期(含归档日期)的平均3天
每周 average of 7 days ending on and including the Saturday file date
Monthly 日历月内所有数据的平均值

请注意,所有海洋测量都被包装在0.25°地图(约manbet客户端2.0万博吧25公里网格)上。然而,每个地球物理参数的有效空间分辨率由上面列出的如表2中所列的检索中使用的频率信道确定。

The details of the ocean measurements in the gridded binary files are listed below.

表3:RSS Windsat海洋测量产品详情。manbet客户端2.0万博吧测量以数据文件中包含的顺序提供。
缩写 产品
姓名
产品Description Scale 抵消 有效数据范围 Reason for no data
时间 时间 格林威治标准时间午夜后的分钟数
Fractional hour of day GMT
6.0
01
0
0
0到1440.
0.0至24.0
没有数据
不锈钢 Sea surface temperature Temperature of top layer (skin) of water ~1 mm thick 0.15 -3.0 -3至34.5° high winds (<20 m/s), sun glint, rain, RFI, near sea ice or land (~75 km)
wspd_lf. 10米风速 风速使用10.7 GHz频道及以上 0.2 0 0.至50.0 m / s 阳光闪耀,雨,rfi,海冰或土地附近(〜50公里)
wspd_mf. 10米风速 风速使用18.7 GHz频道及以上 0.2 0 0.至50.0 m / s 阳光闪耀,雨,rfi,海冰或土地附近(〜50公里)
水蒸气 柱状大气水蒸气 包含在大气的垂直柱中的总气水 0.3 0 0to 75.0 mm
1gm/cm2=10毫米
大雨或近陆(约25公里)
CLOUD Columnar cloud liquid water Total cloud liquid water contained in a vertical column of the atmosphere 0.01 -0.05 -0.05至2.45 mm 靠近陆地(约25公里)
RAIN Rain rate 液体水沉淀率 01 0 0.到25.0 mm / hr 靠近陆地(约25公里)
华盛顿特区 全天候10-M风速 风speed derived using all channels and three separate algorithms to obtain winds in all weather conditions 0.2 0 0.至50.0 m / s sun glint, RFI, near sea ice or land (~75 km in rain, ~50 km no rain)
WDIR. 10-m wind direction 海洋公约风向,相对于北方 1.5 0 0to 360.0 deg 低风(<3米/秒),RFI,雨> 15毫米/小时,阳光,海冰或土地附近(〜50公里)

The daily files consist of WindSat ocean measurements mapped to a regular grid complete with data gaps between orbits. Two maps exist for each parameter, one of descending orbit segments (local morning passes) and the other of ascending orbit segments (local evening passes). Daily data files contain time maps consisting of the UTC observation time for each set of passes (descending and ascending). Time-Averaged data files do not contain any time information.

Each daily binary data file available from ourFTP网站由十八0.25 x 0.25度网格(1440,720)字节映射组成。九个下降(早晨)地图按以下顺序提供:时间(时间),海面温度(SST),10米表面风速,低频(WSPD_LF),10米表面风速,中频(WSPD_MF),大气水蒸气(蒸气),云液体水(云),雨率(雨),全天天气10米表面风速(WSPD_AW)和表面风向(WDIR)。九个上升(晚上)地图以相同的顺序遵循。

每日,3天和每月文件位于目录中/windsat/bmaps_v07.0.1/yYYYY/mMM。相应的文件名约定是wsat_yyyyyymmmddv7.gz,wsat_yyyyyymmmddv7_d3d.gz和wsat_yyyyymmv7.gz。每周文件位于目录中/windsat/bmaps_v07.0.1/weeks/,文件名约定wsat_yyyyymmddv7.gz其中:

yyyy. 2010, 2011 etc.
mm 09,10等。
DD. day 01、02等。

The center of the first cell of the 1440 column and 720 row map is at 0.125 E longitude and -89.875 latitude. The center of the second cell is 0.375 E longitude, -89.875 latitude.

数据值下降到0到25​​5.如下所示保留特定值:

0到250. = 有效的地球物理数据
251. = missing because of bad data quality (sun glint; RFI); missing SST, WSPD_LF or WSPD_MF because of rain; missing data because near sea ice; missing VAPOR because of heavy rain; missing SST because of high wind speed (greater than 20 m/s); missing data due to land proximity.
252. = 海冰,或可能的海冰污染
253. = 存在的观察结果,但坏了(不用于复合地图)
254. = 没有观察
255. = 土地群众

需要缩放0和250之间的数据值以获得有意义的地球物理单位。为了缩放数据,乘以表3中列出的缩放因子(并添加偏移)。

所有二进制数据文件都有gzip压缩以减小大小和减少传输时间。它们应该以二进制模式下载。

关于覆盖相邻卫星过程的说明

极地轨道卫星的连续测量在高纬度(>60度)和manbet客户端2.0万博吧一天的开始/结束部分重叠。在制作将测绘带数据放置在地球网格上的每日地图时,我们可以平均不同测绘带的观测值,选择早期观测值,或者用后期观测值覆盖早期观测值。对于除WindSat以外的所有RSS卫星产品(SSM/I、SSMIS、AMSR-E、TMI、QuikSCAT),当观测值之间的时差大于50分钟时,通过覆盖早期观测值来创建每日地图。对于WindSat,我们使用早期观测值,除非观测值丢失,否则不覆盖。这样做是为了使给定的0.25度单元的所有地球物理参数都参考相同的观测时间。WindSat比其他卫星更复杂,因为每个频率通道(因此每个地球物理参数)都有不同的观测几何结构,因此时间略有不同。如果我们用后来的观测覆盖早期的WindSat观测,将会在低分辨率通道的高纬度地区,特别是在swath边缘造成巨大的数据缺口。

Browse Imagery on Web Site

我们网站上每天、三天、每周和每月的图形图像显示一个海洋测量:海面温度(SST)、10米低频分辨率表面风速(WSPD\ U LF)、10米中频分辨率表面风速(WSPD\ U MF)、柱状水汽(Vapor)、云液态水(Cloud)、降雨率(Rain),10米地面全天候风速(WSPD\ U AW)和风向(WDIR)。显示的数据日期是WindSat观测时的UTC日期/天。每个浏览图像的比例都位于地图旁边以供参考。虽然表3给出了有效数据范围(从最小到最大),但浏览图像中的比例尺设置为直观地增强数据,并且可能会有所不同。

In the browse images white areas represent regions of likely sea ice contamination as determined by the WindSat field of view. In the time-averaged maps, ice is indicated when ice is present over 50% of the time, or when the number of times a cell is identified as containing ice is greater than the number of times the cell contains data. Land regions are colored gray. Those areas where WindSat data are not available are black. The black color includes areas where the satellite did not pass over and no data were collected, areas where data were collected but were determined to be bad, coastal areas, areas affected by sun glint on the SST and wind speed maps, areas near sea ice on the SST and wind speed maps, areas of rain on the SST and wind speed maps, areas of heavy rain on the water vapor map, areas of high wind speed (>20 m/s) on the SST map, and areas of RFI (radio frequency interference).

浏览我们网站上的图像显示NRT(“rt”)数据,而它是可用的,并最终数据之后。

日常中的差距和为期3天的产品reduce the number of observations in weekly and monthly average products. When you browse through the images we have on our web site, the navigation may skip dates for which there are no data, or you may see a blank map stating that no data are available for that time. Binary data files for dates with completely missing data are not produced and they will be absent from our FTP server.

Data Access

温莎data products are available for the time period from just after launch, Feb 2003 to the present. As with all the other RSS satellite products, the data are provided in a gridded, binary format file. Graphic browse images of the ocean measurements can be在我们的网页上查看可以从我们的FTP服务器下载二进制数据文件:ftp.ssmi.com/windsat

二进制文件读取例程和验证文件在我们的ftp服务器上提供windsat/support目录。

相关数据集

Windsat数据也可从NASA PO.DAAC获得NETCDF格式。这些文件中存在相同的海洋测量值manbet客户端2.0万博吧。包括元数据。

RSS水蒸气值包括在RSS TPW 1-DEG网格产品中。

Sea Surface Temperatures from WindSat are extracted and included in the RSS OISST daily product and the L2P GHRSST files.

工具书类

Meissner, T., and F. J. Wentz, (2012),海面的发射率在6至90 GHz之间的大范围的风速和地球发射角度, IEEE Trans. on Geoscience and Remote Sensing, 50(8), 3004-3026.

Meissner,T.,L. Ricciardulli和F. J.Ventz,2011年,来自互际主动和无源微波卫星传感器的全天候风矢量测manbet客户端2.0万博吧量,纸在2011年IGARS会议上呈现,加拿大卑诗省温哥华。

Gaiser,P.等,2004年,Windsat Space Forne Polarimetric微波辐射计:传感器描述和早期轨道性能,IEEE Trans。在地质上。和遥感,42(11),pp。2347-2361。

Meissner,T.,L.Ricciardulli和F.J.Wentz,2010年,The RSS WindSat version 7 all-weather wind vector product,在西班牙巴塞罗那国际海洋矢量风会议上发表的论文。

Meissner,T.,L.Ricciardulli和F.J.Wentz,2010年,来自主动和manbet客户端2.0万博吧无源微波传感器的风测量:雨中的高风和风,纸呈现在2010年乌尔西微波签名2010年,佛罗伦萨,意大利。

Meissner,T.和F.J.Wentz,2009年,风向量检索在雨下与被动卫星微波辐射尺,IEEE地球科学与遥感学报,47(9),3065-3083。

Meissner, T. and F. J. Wentz, 2006,Windsat海洋检索:辐射转移模型,算法,验证,纸张在第9位微波辐射测定和遥感应用中举行的专家会议,USA Puerto Rico。

致谢

Windsat数据由遥感系统生产,并由NASA物理海洋学计万博体育app网页注册划赞助。RSS Windsat数据可用www.dj-hx.com.。我们感谢在Noaa / Nesdis / Star的华盛顿,DC和Paul Chang海军万博网址是什么研究实验室的Peter Gaiser,为我们提供Windsat TDR数据。

How to Cite These Data

Continued production of this data set requires support from NASA. We need you to be sure to cite these data when used in your publications so that we can demonstrate the value of this data set to the scientific community. Please include the following statement in the acknowledgement section of your paper:

“温莎data are produced by Remote Sensing Systems and sponsored by the NASA Earth Science MEaSUREs DISCOVER Project and the NASA Earth Science Physical Oceanography Program. RSS WindSat data are available atwww.dj-hx.com.。“

An official data citation for use in publications is given below. Insert the appropriate information in brackets.

Wentz,F.J.,L.ricciardulli,C.Gentemann,T. Meissner,K.A.Hilburn,J. Scott,2013:遥感系万博体育app网页注册统Coriolis Windsat [指示您是否每天使用,3天,每周或每月]环境套件在0.25°Grid 7.0.1版上,[表示子集,如果使用,则表示子集]。万博体育app网页注册遥感系统,圣罗莎,加利福尼亚州。在线提供2019新万博appmanbetⅩ 。[访问DD MMM YYYY]。