温莎特

介绍

Windsat Polariemetric辐射计是由海军研究实验室(NRL)遥感师和美国海军的空间技术的海军中心开发的。乐动帐号注册它于2003年1月6日推出,位于国防部科里奥利卫星部。Windsat意味着展示了全极化辐射计的能力,以测量来自空间的海洋表面风向量。在发布之前,唯一能够测量海洋风矢量的仪器是散射仪(有源微波传感器)。除了风速和方向外,仪器还可以测量海面温度,土壤水分,冰雪特性,水蒸气,云液体水和雨率。

Instrument Description

For a detailed description of the WindSat instrument, see P.Gaiser, "Windsat Spangeborne Polarimetric微波辐射计:传感器描述和早期轨道性能“。Windsat在近极轨道上的科里奥利卫星进行操作。本地上升节点时间保持在下午6点。这意味着仪器在6点以北方传播到北方和您所在地点的赤道上。这段时间附近的表面取决于你的纬度。

WindSat辐射计校准和控制ains the lower frequency channels required for SST retrievals. The radiometer operates in 5 discrete channels: 6.8, 10.7, 18.7, 23.8 and 37.0 GHz. All are fully polarimeteric except the 6.8 and 23.8 GHz channels that have only dual polarization. Table 1 summarizes the channel details. The feedhorns of each frequency channel trace out different arcs along the scan, therefore the Earth Incidence Angles (EIA) are different for each frequency band. Unlike previous radiometers, the WindSat sensor takes observations during both the forward and aft looking scans. This makes the WindSat geometry of the earth view swath quite different and significantly more complicated to work with than the other passive microwave sensors. The RSS WindSat products are the only dataset available that uses both the fore and aft look directions. By using both directions, we obtain a wider swath and more complicated swath geometry as is visible in the browse images.

表1:帆板通道的概要,偏振射线入射角和沟道分辨率。偏振被列为垂直,H用于水平,P对于+45°,L为左圆形,以及右圆形的v。
Band [GHz] 偏振 Average EIA

[deg]

Spatial Resolution
(3-dB footprint size)

[km x km]

6.8 v,H. 53.8 39 x 71.
10.7 v,h,p,m,l,r 50.1 25 x 38.
18.7 v,h,p,m,l,r 55.6 16 x 27
23.8 v,H. 53.2. 20 x 30.
37.0 v,h,p,m,l,r 53.2. 8 x 13

在发布后结账期后,Windsat数据于2003年2月5日开始。随着一些短期的非操作时段,仪器在目前的时间内继续运行。数据差距通常是由于我们的处理设施上游的数据缺失,例如仪器已关闭。偶尔,最近录制的数据获得和/或处理有延迟。如果数据不在几周后不存在,则丢失的数据不太可能将可用。我们保留缺失数据的记录:Windsat差距列表

Data Processing

我们从NRL和NOAA获得Windsat天线温度数据。通过使用这两个来源,我们的目标是为科学家提供完整的一组数据,因为他们的研究。乐动帐号注册使用一致的处理方案和稳健的辐射传输模型,我们将挡风玻璃数据与其他微波辐射尺寸互相互相,获得亮度温度,然后产生我们的海洋测量产品进行分配。Windsat海洋产品包括海面温度(SST);各种表面风速和方向;大气水蒸气;云液体水;和雨率。

乐动体育下载遥感系统以两个阶段执行indsat仪器数据的详细处理。第一阶段产生近实时(NRT)产品(由文件名内的“RT”标识),我们可以尽快提供。这通常在记录数据的3小时内,除了偶尔接收或处理数据时偶尔延迟。虽然适合许多及时的用途,但差异可能出现微妙,但NRT产品并非旨在是档案/研究质量。乐动帐号注册它们将在一周内删除,不应存档。

The "Final" data (identified by "v7.0.1" within the file name) are processed when we receive the NCEP FNL analysis. The NCEP wind directions are particularly useful for retrieving more accurate SSTs and wind speeds. The final "v7.0.1" products will continue to accumulate new swaths (half orbits) until the maps are full, generally within 7 days. Occasionally, data become available after more lengthy delays, and such data will be added to final "v7.0.1" products. Thus, final refers to the type of swath processing, and does not imply that a data file is finalized (as in, will never change). Newly available data swaths will be added to final "v7.0.1" products as we obtain data from our sources.

涉及Windsat数据处理的几个步骤:

  1. 美国海军研究实验室乐动帐号注册提供RSS与Level-1A天线温度的RS,也称为温度数据记录(TDR)。我们将数据处理到水平-2a校准的大气亮度温度(TBS)的顶部。在此校准程序的最重要问题是讨论的GMI ATBD.
  2. The top of the atmosphere TB are then optimally interpolated onto a fixed 0.125 degree Earth grid, from which the various ocean measurements are retrieved. The products available on our ftp site are then created by simple bin resampling to a 0.25 deg grid. Though each product is placed on this 0.25 deg grid,the effective resolution of the data varies. The following table gives an overview of the WindSat ocean measurements in the order they appear in the binary files, and lists each product's effective spatial resolution.

表2:RSS二进制数据文件中提供的订单中的Wi乐动苹果手机乐动体育官方2.0ndsat海洋测量值。每个测量的有效空间分辨率从数据映射到的0.25°Grid。通道偏振被列为垂直,H用于水平,P对于左圆形,L为左右的v,以及右圆形的v。
海洋测量 Acronym Effective Spatial
Resolution [km x km]
所需频道
检索
Time TIME N/A N/A
海表面温度 SST 39 x 71. 6.8 VH, 10.7 VH,18.7 VH, 23.8 VH, 37.0 VH
Ten-meter wind speed using low frequency channels WSPD_LF 25 x 38. 10.7 VH, 18.7 VH, 23.8 VH, 37.0 VH
使用中频通道十米风速 WSPD_MF 16 x 27 18.7 VH, 23.8 VH, 37.0 VH
Columnar atmospheric water vapor 16 x 27 18.7 VH, 23.8 VH, 37.0 VH
柱状云液体水content 16 x 27 18.7 VH, 23.8 VH, 37.0 VH
雨率 8 x 13 18.7 VH, 23.8 VH, 37.0 VH
全天候10米风速 wspd_aw. 25 x 38没有下雨

39 x 71在雨中

6.8 VH, 10.7 VH, 18.7 VH, 23.8 VH, 37.0 VH
十米风向(相对于北) WDIR 25 x 38. 10.7 VHPMLR,18.7 VHPMLR,23.8 VH,37.0 VHPMLR

如果没有用于地球物理参数所需的通道,则无法完成检索。For example, this could result in VAPOR retrievals for a given location, but not WSPD_LF or SST in the same location. SST retrievals are often missing at the center of the swaths because there are no 6.8 GHz observations. Wind direction is not available at the edge of the swaths because there are no polarimetric observations. This "missing data" appearance is different than for other RSS radiometer products.

RSS WindSat Data Products

当前版本的遥感系统Windsat数据产品是V7乐动体育下载.0.1 Windsat数据于2013年8月再处理,以删除影响2008年1月之后的风速和方向的轻微处理错误。产品文件中的所有其他数据与以前的版本相同-7释放。我们每天提供一份文件套件,为期3天,周和月。数据套件包含上面表2中列出的测量值。乐动体育官方2.0乐动苹果手机

Windsat数据产品包括标准的测量集(海面温度,风速,水蒸气,云液体水和雨率),与其他RSS辐射计乐动苹果手机乐动体育官方2.0产品不同,因为我们可以包括额外的测量:

  1. WDIR:由于其偏振通道,Windsat可以测量表面风向。仅提供WDIR,如果风速超过3米/秒,雨率低于15毫米/小时。我们产品中的风向是海洋公约.
  2. wspd_aw.: We have made significant progress in improving the retrieval of wind speeds in the presence of rain. See雨下的风矢量检索与被动卫星微波辐射米,有关所用算法的更多详细信息。如果6.8 GHz通道与所有其他垂直和水平偏振的通道一起使用,我们可以在无雨和雨雨气氛中检索帆板表面风速。我们将各种算法组合,包括通过在所有降雨条件下工作的雨季算法以及针对热带气旋的H-INN算法工作的全球风速。我们的二进制文件中提供的最终全天候风速WSPD_AW是在非下雨条件下获得的标准风速,通过雨水和H型风速推导出风速的标准风速。

除了全天候风速外,我们还生产两个标准的无雨辐射线管风产品:WSPD_LF(低频)和WSPD_MF(中频)。首先,使用10.7GHz及以上的频率通道创建WSPD_LF(参见表1),并且与AMSR-E的风相似。第二个WSPD_MF使用18.7 GHz及以上的频率信道,最类似于SSM / I风。每个风电产品都具有明显的优点。WSPD_LF受到大气和雨的影响较小,但受10.7 GHz RFI和太阳闪光效果影响。WSPD_MF具有更高的有效空间分辨率,冰和土地污染的影响较小,仅受太阳闪光效果的略微影响,以及RFI。WSPD_MF比WSPD_LF有点吵闹。

Gridded Binary Data Files

We produce WindSat Daily and Time-Averaged (3-day, weekly and monthly) binary data files. The files contain no headers or metadata and are a simple set of single-byte arrays as described below. Since the data are stored as single bytes, no byte-swapping when transfering between machines is necessary.

Gridded data files are organized according to observation date. All dates and times are Coordinated Universal Time (UTC), also known as Greenwich Mean Time (GMT), Zulu Time (Z), Universal Time (UT), and World Time. Data products include daily and time averaged measurements as follows:

Daily 轨道数据映射到0.25度网格
divided into 2 sets of maps based on ascending and descending passes
当相邻通过在高纬度和日常“接缝”时,选择早期的数据。(See note below)
3-Day 结尾的平均3天,包括文件日期
Weekly 结束的平均值7天,包括周六文件日期
每月 average of all data within the calendar month

Note that all the ocean measurements are gridded onto a 0.25 deg map (approximately 25 km grid). However, the effective spatial resolution for each geophysical parameter is determined by the frequency channels used in the retrieval as listed in Table 2 above.

下面列出了网格二进制文件中的海洋测量的细节。乐动体育官方2.0乐动苹果手机

Table 3: RSS WindSat ocean measurement product details. Measurements are provided in the order contained in the data files.
Acronym Product
Name
产品描述 规模 Offset Valid Data Range 没有数据的原因
TIME Time 自午夜以来的总格总格
GMT的小小一天
6.0
0.1
0.
0.
0 to 1440
0.0到24.0.
no data
SST 海表面温度 水的温度(皮肤)水〜1毫米厚 0.15 -3.0 -3 to 34.5 deg 高风(<20米/秒),太阳闪光,雨,RFI,海冰或土地附近(〜75公里)
WSPD_LF 10-m wind speed 风speed using 10.7 GHZ channels and above 0.2 0. 0. to 50.0 m/s sun glint, rain, RFI, near sea ice or land (~50 km)
WSPD_MF 10-m wind speed 风speed using 18.7 GHZ channels and above 0.2 0. 0. to 50.0 m/s sun glint, rain, RFI, near sea ice or land (~50 km)
Columnar atmospheric water vapor Total gaseous water contained in a vertical column of the atmosphere 0.3 0. 0.至75.0毫米
1gm / cm2 = 10 mm
heavy rain or near land (~25 km)
柱状云液体水 包含在大气的垂直柱中的云液体水 0.01 -0.05 -0.05 to 2.45 mm near land (~25 km)
雨率 Rate of liquid water precipitation 0.1 0. 0. to 25.0 mm/hr near land (~25 km)
wspd_aw. All-weather 10-m wind speed 使用所有通道和三个单独的算法导出的风速,以获得所有天气条件的风 0.2 0. 0. to 50.0 m/s Sun Glint,RFI,海冰或土地附近(雨中〜75公里,〜50公里没有下雨)
WDIR 10米风向 Oceanographic-convention wind direction, relative to north 1.5 0. 0.至360.0° low winds (< 3 m/s), RFI, rain > 15 mm/hr, sun glint, near sea ice or land (~50 km)

日常文件由Windsat海洋测量组成,映射到常规网格,完成轨道之间的数据间隙。乐动体育官方2.0乐动苹果手机每个参数都存在两种地图,其中一个降序轨道段(当地晨报)和另一个升序轨道段(当地傍晚的通行证)。每日数据文件包含由每组通行证的UTC观察时间(降序和升序)组成的时间映射。时间平均数据文件不包含任何时间信息。

我们的每份日常二进制数据文件ftp siteconsists of eighteen 0.25 x 0.25 degree grid (1440,720) byte maps. Nine descending (morning) maps are provided in the following order: Time (TIME), Sea Surface Temperature (SST), 10-meter Surface Wind Speed at Low Frequency (WSPD_LF), 10-meter Surface Wind Speed at Medium Frequency (WSPD_MF), Atmospheric Water Vapor (VAPOR), Cloud Liquid Water (CLOUD), Rain Rate (RAIN), All-Weather 10-meter Surface Wind speed (WSPD_AW), and Surface Wind Direction (WDIR). Nine ascending (evening) maps follow in the same order.

Daily, 3-day and monthly files are located in the directory/windsat/bmaps_v07.0.1/yyyyy/mmm.. The respective file name conventions are wsat_yyyymmddv7.gz, wsat_yyyymmddv7_d3d.gz, and wsat_yyyymmv7.gz. Weekly files are located in the directory/windsat/bmaps_v07.0.1/weeks/, with the file name convention wsat_yyyymmddv7.gz where:

yyyy year 2010年,2011年等
毫米 month 09, 10, etc.
dd 01,02等。

1440列和720行地图的第一电池的中心处于0.125 e经度和-89.875纬度。第二个电池的中心是0.375 e经度,-89.875纬度。

The data values fall between 0 and 255. Specific values have been reserved as shown below:

0 to 250 = valid geophysical data
251 = 由于数据质量不好(Sun闪烁; RFI)缺少;缺少SST,WSPD_LF或WSPD_MF,因为雨;缺少数据,因为海冰附近;由于大雨而缺少蒸汽;由于风速高(大于20米/秒),缺少SST;由于陆地接近缺少数据。
252 = sea ice, or likely sea ice contamination
253 = observations exist, but are bad (not used in composite maps)
254 = no observations
255 = land mass

The data values between 0 and 250 need to be scaled to obtain meaningful geophysical units. To scale the data, multiply by the scale factors (and add the offsets) listed in Table 3.

所有二进制数据文件都有GZIP压缩,以减小大小和减少转移时间。它们应该以二进制模式下载。

关于覆盖邻近卫星通行证的注意事项

来自极地轨道卫星的连续测量的仪表部分在高纬度乐动苹果手机乐动体育官方2.0(> 60度)和一天的开始/结束时部分重叠。在生成将SWATH数据放置在地球网上的日常地图时,我们可以从不同的条件中平均观察,选择早期的观察或通过后续观察来重写早期观察。对于所有RSS卫星产品(SSM / I,SSMIS,AMSR-E,TMI,QuikScat)除外,Windsat除外,每日地图是通过覆盖早期观察,当观察之间的时间差超过50分钟时创建。对于Windsat,除非缺少观察,否则我们使用早期观察,不要覆盖。这是为了使给定的0.25-Deg单元格的所有地球物理参数都参考相同的观察时间。Windsat比其他卫星更复杂,因为每个频率通道(并且因此每个地球物理参数)具有不同的观察几何形状,因此具有略微不同的时间。如果我们要用后期观察覆盖早期的帆板观察,它将在低分辨率通道中引起高纬度的大数据间隙,尤其是在条形边缘。

在网站上浏览图像

每个每天,为期3天,每周和每月的图形图像放大e on our web site displays one ocean measurement: Sea Surface Temperature (SST), 10 meter Surface Wind Speed at low frequency resolution (WSPD_LF), 10 meter Surface Wind Speed at medium frequency resolution (WSPD_MF), Columnar Water Vapor (VAPOR), Cloud Liquid Water (CLOUD), Rain Rate (RAIN), 10 meter surface All-Weather Wind Speed (WSPD_AW), and Wind Directions (WDIR). The date of the data displayed is the UTC date/day when WindSat made the observation. The scale for each browse image is located next to the map for reference. Though the valid data range (minimum to maximum) is given in Table 3, the scale bars in the browse images are set to visually enhance the data and may vary.

在浏览图片中,白色区域代表可能的海冰污染的区域,如帆黑的视野所确定的。在时间平均的地图中,当冰存在超过50%的时间时,或者当识别为包含冰的次数时,冰的次数大于单元格包含数据的次数。陆地区是灰色的。Windsat数据不可用的那些区域是黑色的。黑色包括卫星未通过的区域,没有收集数据,收集数据但被确定为坏,沿海地区,受SST和风速地图影响的区域,海冰附近的区域在SST和风速地图上,SST和风速地图的雨区,水蒸气地图的大雨区域,SST地图上的风速(> 20米/秒),以及RFI的区域(射频干扰)。

Browse imagery on our web site display NRT ("rt") data while it is available, and final data thereafter.

每日和3天产品内的差距还减少了每周和每月平均产品的观察数。当您浏览我们的网站上的图像时,导航可能会跳过没有数据的日期,或者您可能会看到一个空白地图,说明该时间没有数据。没有生成具有完全缺失数据的日期的二进制数据文件,并且我们将从我们的FTP服务器中缺席。

数据访问

Windsat数据产品可在2003年2月至今发布后的时间段。与所有其他RSS卫星产品一样,数据以网格化的二进制格式文件提供。图形浏览海洋测量的图像可以是乐动体育官方2.0乐动苹果手机viewed on our web pageand the binary data files can be downloaded from our ftp server:ftp.ssmi.com/windsat..

在我们的FTP服务器上提供二进制文件读取例程和验证文件帆板/支撑directory.

Related Data Sets

The WindSat data are also available from NASA PO.DAAC in netCDF format. The same ocean measurements exist in these files. Metadata are included.

温莎特water vapor values are included in the RSS TPW 1-deg gridded product.

来自Windsat的海面温度被提取并包含在RSS OISST日常产品和L2P GHRSST文件中。

References

Meissner,T.和F. J.Ventz,(2012),The emissivity of the ocean surface between 6 - 90 GHz over a large range of wind speeds and Earth incidence angles,IEEE Trans。在地球科学和遥感,50(8),3004-3026。

Meissner, T., L. Ricciardulli, and F. J. Wentz, 2011,All-weather wind vector measurements from intercalibrated active and passive microwave satellite sensors, paper presented at 2011 IGARSS meeting, Vancouver, BC, Canada.

Gaiser, P. et al, 2004, The WindSat space borne polarimetric microwave radiometer: sensor description and early orbit performance, IEEE Trans. on Geosci. and Remote Sensing, 42(11), pp. 2347-2361.

Meissner,T.,L. Ricciardulli和F. J.Ventz,2010年,RSS Windsat版本7全天候风矢量产品,纸在国际海洋矢量风会议上呈现,巴塞罗那,西班牙。

Meissner,T.,L. Ricciardulli和F. J.Ventz,2010年,风从活跃和乐动苹果手机乐动体育官方2.0不测量sive Microwave Sensors: High Winds and Winds in Rain, paper presented at URSI-F Microwave Signatures Meeting 2010, Florence, Italy.

Meissner,T.和F. J.Ventz,2009年,风Vector Retrievals Under Rain With Passive Satellite Microwave Radiometers,地球科学和遥感的IEEE交易,47(9),3065-3083。

Meissner,T.和F. J.Ventz,2006年,Ocean retrievals for WindSat: Radiative transfer model, algorithm, validation, paper presented at 9th Specialist Meeting on Microwave Radiometry and Remote Sensing Applications, Puerto Rico, USA.

Acknowledgements

温莎特data are produced by Remote Sensing Systems and sponsored by NASA Physical Oceanography Program. RSS WindSat data are available atwww.dldq88.com. We are grateful to Peter Gaiser at the Naval Research Laboratory in Washington, DC and Paul Chang at NOAA/NESDIS/STAR for providing us with WindSat TDR data.

如何引用这些数据

继续生产此数据集需要支持NASA。我们需要您在出版物中使用时务必引用这些数据,以便我们可以展示向科学界的数据的价值。乐动软件下载请在纸质的确认部分中包含以下声明:

“Windsat数据是由遥感系统生产的,由美国宇航局地球科学乐动体育下载措施发现项目和美国宇航局地球科学物理海洋学学计划。RSS Windsat数据可供选择www.dldq88.com. "

下面给出了用于出版物的官方数据引文。乐动软件下载在括号中插入适当的信息。

Wentz, F.J., L.Ricciardulli, C.Gentemann, T. Meissner, K.A. Hilburn, J. Scott, 2013: Remote Sensing Systems Coriolis WindSat [indicate whether you used Daily, 3-Day, Weekly, or Monthly] Environmental Suite on 0.25 deg grid, Version 7.0.1, [indicate subset if used]. Remote Sensing Systems, Santa Rosa, CA. Available online at乐动体育app . [Accessed dd mmm yyyy].