TMI

Instrument Description Data Processing 二进制文件 数据访问 Related Data 数据使用政策

Introduction

热带降雨测量任务(TRMM)launched November 27, 1997 carrying 5 instruments, one of which is the TRMM Microwave Imager (TMI). TMI is a multi-channel, dual polarized, conical scanning passive microwave radiometer designed to measure rain rates over a wide swath under the TRMM satellite. The design of the instrument was similar to that of other satellite radiometers but the resolution of data measurement was better due to the lower altitude of the satellite orbit. TRMM traveled in a semi-equatorial orbit with an inclination of 35 deg. This type of orbit precessed approximately 7 degrees per day allowing for TMI to sample the surface at all times of day as opposed to the twice per day windows of the polar-orbiting radiometers. TRMM was a joint program between NASA and the Japan Aerospace Exploration Agency (JAXA). In addition to rain rates, TMI also measured sea surface temperatures (SST), ocean surface wind speeds, columnar water vapor, and cloud liquid water. The SSTs from TMI were the first satellite microwave SSTs available and have proven to be of great value to many areas of research.

The initial production of this data set was a collaborative effort with the TRMM Project at NASA Goddard Space Flight Center and the Passive Microwave Earth Science Information Partnership (ESIP) for Climate Studies. The Passive Microwave ESIP (PM-ESIP) was established to provide climate products derived from satellite microwave radiometers and was a joint effort among NASA's Global Hydrology and Climate Center, the University of Alabama in Huntsville, and Remote Sensing Systems. When the PM-ESIP project finished, we continued TMI data processing and product delivery using funds from the NASA MEaSUREs program.

Instrument Description

For a detailed description of TRMM, see theeoportal目录。TMI在TRMM卫星上运行。它有5个频道如下表所述。两个外部校准靶(一个冷,一个热)用于在测量时间内保持一致性。万博吧manbet客户端2.0在发布后结账期后,数据于1997年12月7日开始,并于4月8日结束,当仪器关闭时。TRMM于2001年8月经历了轨道推动,以增加卫星和仪器的寿命。这促进了高度(从350公里到400公里)允许更多多年的操作。但是,从2014年中期开始TRMM orbit started to declineas there was insufficient fuel remaining to maintain the orbit. RSS continued routine data processing until April 6th 2015 just before the TRMM satellite was shut down on April 8th, 2015.

下表提供了预增压高度的每个通道的空间分辨率。在2014 - 2015年下降期间,测量的占用尺寸不断变化。万博吧manbet客户端2.0卫星经常经历了每2至4周的每2至4周的180°Deg偏航机动。TRMM于2015年6月16日进入大气。

乐队[GHz] 极化 空间分辨率(3 dB占地面积大小)
预增压/后升压[km x km]
10.65 v,H. 63 x 37 / 72 x 43
19.35 v,H. 30 x 18 / 35 x 21
21.3 V. 23 x 18 / 26 x 21
37.0 v,H. 16 x 9/18 x 10
85.5 v,H. 7 x 5/8 x 6

Data Processing

We obtained TMI brightness temperature data files (TDRs) from NASA Goddard and reverse engineered the data back to raw radiometer counts. Using a consistent processing scheme and a robust radiative transfer model, we intercalibrated the TMI data with the other microwave radiometers, obtained brightness temperatures, and then produced our ocean measurement products for distribution. The current version of the RSS radiative transfer model and radiometer processing code is called Version-7 (V7). This carefully applied intercalibration yields consistent products from all microwave radiometer data processed at RSS.

对...的描述更新电影剧情海洋产品总结了变化。最重要的是,数据文件格式已更改。一份文件已提交给气候杂志,以详细描述了对TMI界面,地理位置和数据处理的变化。

RSS TMI数据产品

RSS TMI数据文件包含:海面温度,表面风速,大气水蒸气,云液体水和雨率。我们使用强大的辐射传输模型来帮助从仪器亮度温度中获得海洋测量。万博吧manbet客户端2.0该方法在由RSS处理的所有辐射计中是一致的。已经进行了适当的调整,以考虑信道频率的小差异。

当前版本的TMI数据是V7.1 TMI V7.1数据于2015年1月发布。不再使用先前的版本(V4)。有几种改进使V7.1最适合气候研究的最佳数据集。所做的重大变化总结在V.7 document

Similar to AMSR-E, AMSR2, and WindSat, two surface wind speeds are provided for TMI. The first is a surface wind speed derived primarily from the 11 GHz channel and above (we refer to this as the Low-Frequency wind product, WSPD-LF). The second surface wind speed retrieval relies on measurements made by the 37 GHz channels and above like those available for SSM/I (we refere to this as the Medium-Frequency wind product, WSPD-MF). We find these two wind products are very similar with some small differences near rain and land. When comparing winds from TMI and SSMI, the WSPD-MF values must be used. Like the sea surface temperatures, the 11GHz surface wind speeds have small regions of missing data that occur where the sunlight reflects off the ocean surface (also called "sun glint"). Where there is sunglint, affected data are removed.

Similar to other microwave radiometers, the growing problem of射频干扰(RFI)produces bad data if not removed. RFI occurs in large regions where geostationary tv broadcast or telecommunication signals in the microwave range reflect off the ocean and are observed by the radiometer. RFI can also occur in small regions due to emitting sources on the surface where microwave-range signals are used. We now remove any RFI-affected data using a semi-automated process consistently applied to all RSS data sets.

网格二进制数据文件

RSS TMI数据作为日常地图提供(分为上升和降序轨道段),3天均值图,每周平均地图和每月平均地图。所有图像涵盖全局区域,其具有从40s到40n的有效数据,以0.25°(〜25公里)的像素分辨率。文件不包含标题或元数据,并且是一组简单的单字节数组。由于数据存储为单个字节,因此在计算机之间传输时不需要字节交换。这些网格数据根据观察日期组织。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。数据产品包括日常和时间平均的地球物理数据如下:

日常 orbital data mapped to 0.25 degree grid
根据升序和下行通行证分为2个地图
early data may be overwritten by later data at high latitudes and at the daily "seam"
3天 结尾的平均3天,包括文件日期
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

这些数据中存在差距。缺少数据通常会影响每日和3天的产品,但也可以在每周和每月平均值中减少观察数(以及由此质量)。

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。

Each DAILY binary data file available from our ftp site consists of fourteen 0.25 x 0.25 degree grid (1440,720) byte maps. Seven ascending maps in the following order: Time (T), Sea Surface Temperature (S), 10-meter Surface Wind Speed using 11 GHz (WSPD-LF), 10-meter Surface Wind Speed using 37 GHz (WSPD-MF), Atmospheric Water Vapor (V), Cloud Liquid Water (L), and Rain Rate (R), are followed by seven descending maps in the same order.

缩写 产品
姓名
产品
描述
Scale 抵消 有效数据范围 Reason for No Data
TIME Time 自午夜以来的总格总格
Fractional hour of day GMT
6.0
0.1
0.
0.
0 to 1440
0.0到24.0.
no data
SST Sea surface temperature 顶层(皮肤)的温度
水〜1毫米厚
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speed using 10.7 GHz channel 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 使用18.7 GHz频道的风速 0.2 0. 0.至50.0 m / s 太阳闪耀,雨rfi,靠近海冰或土地(〜50公里)
柱状大气水蒸气 包含的全气态水
垂直柱的大气
0.3 0. 0. to 75.0 mm
1 gm/cm2= 10mm
heavy rain, sea ice or near land (~25 km)
CLOUD Columnar cloud liquid water 含有总云液体水
垂直柱的大气
0.01 -0.05 -0.05至2.45 mm near sea ice or land (~25 km)
RAIN 雨率 Rate of liquid water precipitation 0.1 0. 0.到25.0 mm / hr near sea ice or land (~25 km)

有两种情况下,邻居数据的差别是重叠的。在更高的纬度下,轨道段在局部区域内重叠,并且在短测量时间内重叠。在这些情况下,提供参数数据,提供了通过连续的轨道(分开50分钟)测量它们。在第二种情况下,每张地图上存在“接缝”,其中当天的第一和最后轨道段重叠。该接缝处的数据不平均。这里,来自这一天的最后一个数据覆盖了在一天开始时测量的第一个数据。

DAILY, 3-day and monthly files are located in the directory/tmi/bmaps_v07.1/yYYYY/mMM。Each daily file name has the convention: yyyymmddv7.1.gz. The 3-day and monthly files have the conventions F12_yyyymmddv7.1_d3d.gz and F12_yyyymmv7.1.gz. Weekly files are located in the directory/tmi/bmaps_v07.1/weeks/, with the file name convention F12_yyyymmddv7.gz where

fs 文件说明符 F12
yyyy. 1997年,1998年等
毫米 month 09,10等。
DD. 01, 02, etc.

As an example, TMI daily data for March 5, 1999 is located in: /tmi/bmaps_v07.1/y1999/m03/F12_19990305v7.1.gz

1440列和320行地图的第一电池的中心为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。数据值均为0到255.已保留特定值:

0到250 = valid geophysical data
251 = 由于雨,由于雨而缺少水速或缺少水蒸气
252 = *未在此数据集中使用*
253 = TMI observations exist, but are bad
254 = 没有TMI观察
255 = land mass

The data values between 0 and 250 need to be scaled to obtain meaningful geophysical data. To scale the data, multiply by the scale factors listed in the table above:

我们FTP站点上可用的3天,每周和每月二进制文件类似于每日TMI二进制文件。它们由六个地图组成,网格尺寸为0.25×0.25。每个文件都可以读取为1440,720,6数组。只有六个地图,因为省略了时间层。所有其他参数都存在于同一顺序。

所有二进制数据文件都具有ZIP压缩,以减小大小和减少转移时间。如果您只需要一个文件,请使用网页上的“下载二进制数据”按钮。如果您访问了大量文件,则使用匿名FTP服务器可能会更方便:ftp.remss.com/tmi.

使用TMI二进制字节映射的进一步帮助位于目录中tmi_support.在我们的FTP网站上。该目录包含用于读取字节映射的示例Fortran,IDL,MATLAB,C ++和Python程序,以及自述文件。

浏览图像

每日,3天,每周或每月网页显示一张海洋测量:海面温度(SST),使用低频通道(WSPD_LF)10米表面风速,使用中频通道10米表面风速(WSPD_MF),柱状水蒸气(蒸气),云液体水(云)和雨率(雨)。在特定的GMT日期收集给定地图的所有数据。关于当地时间进行观察的日期可能因网格经度而变化。使用IDL从公共V7.1 TMI二进制数据文件(上文描述)产生图形图像映射。缩放映射以提高数据可见性,并且不显示整个有效的数据范围。请务必检查地图上的刻度以供参考。这些地图上的陆地区是灰色的。TMI数据不可用的区域是黑色的,包括卫星没有进行测量或雨水禁止准确检索的区域的区域。万博吧manbet客户端2.0

缺失数据

There may be gaps within the provided data. If you select a date for which data are not available, a map with text stating 'Data currently not available' will be posted. When browsing imagery, the navigation may skip dates with no data, or you may see a blank map stating that no data is available for that time. Binary data files for dates with completely missing data are not produced; they will be absent from our FTP server.

有关缺少TMI数据的官方信息,请访问NASA Goddard DAACTRMM Satellite Data Outages

数据访问

TMI data products are available for the time period from just after launch, December 7, 1997 to December 31, 2014. 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.remss.com/

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tmi_support.目录。

Related Data Sets

TMI海面温度数据也是来自PO.DAAC的GHRSST格式L2P NetCDF文件。这些是目前版本-4 TMI数据。

NASA GHRC数据中心提供级别2C SWATH TMI地球物理数据文件。这些文件由海洋地球肉类产品的个体轨道组成:SST,风,蒸气,云和雨率。数据集目前仅在V4中。我们希望很快更新版本-7.1。

References

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 TGRS,50(8),3004-3026。

Gentemann, C. L., T. Meissner and F. J. Wentz, (2010),Accuracy of Satellite Sea Surface Temperatures at 7 and 11 GHz,地球科学和遥感的IEEE交易,48(3),1009-1018。

Hilburn, K. A., and F. J. Wentz, (2008),互补微波海洋检索算法的Intercalibrated被动微波雨水,应用气象与气候学杂志,47,778-795。

Gentemann, C. L., F. J. Wentz, C. A. Mears and D. K. Smith, (2004),In Situ Validation of Tropical Rainfall Measuring Mission Microwave Sea Surface Temperatures,地球物理研究杂志,109,C04021,D​​O万博网址是什么I:10.1029 / 2003JC002092。

Wentz,F.J.,P. D. Ashcroft和C.L.Getemann,(2001),发射后校正程序ion of the TRMM Microwave Imager, IEEE Transactions on Geoscience and Remote Sensing, 39(2), 415-422.

致谢

TMI数据由遥感系统生产,并由NASA赞助。万博体育app网页注册RSS TMI数据可供选择www.dj-hx.com.。We are grateful to NASA Goddard Space Flight Center for providing access to TMI TDR files.

How to Cite These Data

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。manbext万博官网请在纸质的确认部分中包含以下声明:

“TMI数据由遥感系统生产,并由美国宇航局地球科学计划万博体育app网页注册赞助。数据可用2018世界杯狗万滚球app 。"

下面给出了用于出版物的官方数据引文。manbext万博官网在括号中插入适当的信息。

Wentz, F.J.,C. Gentemann, K.A. Hilburn, 2015: Remote Sensing Systems TRMM TMI [indicate whether you used Daily, 3-Day, Weekly, or Monthly] Environmental Suite on 0.25 deg grid, Version 7.1, [indicate subset if used]. Remote Sensing Systems, Santa Rosa, CA. Available online at2018世界杯狗万滚球app 。[访问DD MMM YYYY]。