CCMP Wind Vector Analysis Product

Version 2 CCMP Wind Product

The Cross-Calibrated Multi-Platform (CCMP) gridded surface vector winds are produced using satellite, moored buoy, and model wind data, and as such, are considered to be a Level-3 ocean vector wind analysis product. We have updated the CCMP product, using improved and additional input data.This web site documents the new CCMP V2.0 data set now available from Remote Sensing Systems(RSS).The V2 CCMP processing now combines Version-7 RSS radiometer wind speeds, QuikSCAT and ASCAT scatterometer wind vectors, moored buoy wind data, and ERA-Interim model wind fields using a Variational Analysis Method (VAM) to produce four maps daily of 0.25 degree gridded vector winds. The original CCMP product (V1.1) was originally produced by Bob Atlas and his team with funding from the NASA REASoN and MEaSUREs programs. The或者iginal MEaSUREs product仍然可以从美国宇航局的物理海洋学daac(podaac.jpl.nasa.gov)提供。RSS已过渡CCMP处理代码以使用我们最新的卫星数据观测运行。所有方法都与原始CCMP产品中使用的方法保持相同,并且大多数CCMP处理代码不变,只有轻微的更改,可以补偿不同的操作系统和编译器。

介绍

Gap-free ocean surface wind data of high quality and high temporal and spatial resolution are useful for a variety of purposes and are necessary for studying large scale air-sea interactions affecting the atmosphere and the ocean. Ocean vector winds are dynamic, continually evolving over short time scales. This characteristic makes the production of global, gridded, gap-free wind fields a challenge, especially at temporal scales of less than one day and spatial scales smaller than typical wind features. Accurate research requires ocean vector wind data for a long enough time period to resolve wind-induced patterns such as the El Niño-Southern Oscillation (ENSO) and the Madden-Julian Oscillation (MJO). Remote Sensing Systems has invested many years of research into validating and cross-calibrating passive and active microwave wind retrievals from satellites.

The Variational Analysis Method (VAM) of data assimilation was utilized by Atlas et al. [1996, 2011] to find the most dynamically suitable way to combine satellite observations and in situ wind measurements into gap-free wind fields. The VAM generates a gridded surface wind analysis which minimizes an objective function measuring the misfit of the analysis to the background, the data and certain a priori constraints. The CCMP wind analyses are at temporal and spatial resolutions suitable for scientific study.The CCMP Version 2.0 (V2) data product described here is a continuation of the highly-used original CCMP product(V1.1 available from NASA JPL PO.DAAC) and builds on the decades of careful VAM development. Two peer-reviewed publications (Atlas et al. 1996, Atlas et al., 2011) describe the original CCMP product and (Hoffman et al, 2003) describes the VAM. This documentation describes the new CCMP V2.0 product available from Remote Sensing Systems.

The original V1.1 CCMP product was processed incrementally, over a number of years, in small batches using the satellite data available at the time of processing, and therefore, assimilated inconsistently processed satellite winds. That is, earlier V4 through V6 RSS winds were used for early production years with V7 winds for the later few years of production. Funding for the original CCMP (V1.1) ended in 2012 with no CCMP winds produced since December 2011. There has been considerable demand for the continuation of the CCMP product, so we have transitioned the code to RSS with the purpose of meeting several distinct goals:

  • Extend the product to the present time and continue processing into the future.
  • 使用一致版本的卫星数据进行重新处理。
  • 添加新可用的传感器。
  • Utilize a higher resolution and consistently produced background model wind field throughout the analysis product.

We provide the Level-3.0 (L3.0) and Level-3.5 (L3.5) CCMP V2.0 products in netCDF4 format.

  • L3.0 CCMP v2.0产品包含0.25度全球网格上的U和V矢量风能组件的四个每日地图(00,06,12和18z)。U和V组件相对于真正的北方。L3.0数据还包括在每个位置分析的观测数量(卫星和原位)的地图。
  • The L3.5 CCMP V2.0 contains monthly winds averaged over the calendar month. Vector averages are computed for U and V. The average wind W is computed using a scalar average.
  • Updates to the CCMP V2.0 product will be made roughly twice a year, to complete processing through December and June.
  • The most recent update occurred in March 2018, and CCMP is now updated through December 30, 2017.

Product Development

CCMP数据集结合了交叉校准的卫星微波风和仪器观测,使用变分析方法(VAM)来产生高分辨率(0.25度)网格分析。使用来自许多卫星传播的无源和有源微波仪器的遥感系统衍生的卫星风力检索。万博体育app网页注册RSS将亮度温度水平的辐射仪与0.2度Celsius嵌入,应用精制的海面发射率模型和辐射转移功能来导出表面风。导出的风检索在微波辐射计仪器平台之间非常一致,包括1Manbetx ,1Manbetx ,amsr.,2018世界杯狗万滚球app ,2019新万博appmanbetⅩ , 和GMI。RSS has also developed a geophysical model function for deriving wind speeds and directions from microwave scatterometers, includingQuikSCAT1mantbex 。辐射计和散射仪数据都是有效的ated against ocean moored buoys, which confirm the measurements are in agreement (to within 0.8 m/s) despite the difference in wind measurement and retrieval methodologies. The VAM combines RSS instrument data with moored buoy measurements and a starting estimate (first-guess) of the wind field. The European Center for Medium-Range Weather Forecasts (ECMWF)ERA-Interim Reanalysiswinds are used in the CCMP V2.0 processing as the first-guess wind field. This 0.25 deg model wind field is consistently processed, as opposed to that of the ECMWF operational model for which the model changes over time. All wind observations (satellite and buoy) and model analysis fields are referenced to a height of 10 meters.

CCMP Version-2 Updates

RSS cooperated with Dr. Ross Hoffman and Mark Leidner to transition the maintenance, update, and continued processing of CCMP. Once the transition was confirmed to be accurately functioning, RSS conducted a full reprocessing of the CCMP data set bringing it out of first-look status and delivering a consistently-reprocessed V2.0 data product for public use in scientific research. The version changes associated with the RSS V2.0 CCMP release include:

  • 使用均匀输入和卫星检索,使用RSS版本-7(或更高)海洋辐射传输模型(ORTM)和一致的加工方法生产的所有卫星风。
  • 将CCMP数据集扩展到2015年7月,计划为数据集提供双年度扩展和更新。
  • 从新仪器添加风:Acat Metop-A,AMSR2和GMI。
  • 升级先猜测背景风场。现在使用0.25°,6小时的时代临时再分析风。
  • Use of improved moored buoy data with better quality control, including winds from NDBC, TAO, TRITON, RAMA, PIRATA, and Canadian buoys.
  • Upgrade of the data file format to netCDF4 with CF-1.6 metadata. Each daily file contains four 6-hourly wind analyses and self-describing metadata.

A time series of all input data used in the VAM is shown below. Passive radiometers are plotted in red and active scatterometers are plotted in green. The version of data used for each instrument is provided. The moored buoy winds and ERA-Interim Reanalysis winds are available for the entire data range. Quality controlled buoy data have been obtained from the Pacific Marine Environmental Lab (PMEL), from the National Data Buoy Center (NDBC), and from the Fisheries and Ocean CanadaOceanography and Scientific Data branch(OSD).

Full reprocessing of the entire data set takes approximately 1-2 months. Twice per year, in January and July, we will update the data product to include the past 6 months. For example, in January 2017, we will release June 2016 to December 2016. In transitioning the code to run at RSS, special care was taken to make no changes to the overall approach or the methodology of the original CCMP product. The code was changed, only where necessary, to account for changes in system architecture and compilers. Source code that was needed for the addition of new satellite winds (AMSR2 or GMI) was adapted from already existing code. This type of careful transition ensures that the same high-quality CCMP product is still produced, but with updated satellite, buoy and model wind data as input.

Data Product Format

The CCMP V2.0 Level-3.0 (L3.0) winds are available as netCDF-4 data files. Each L3.0 daily data file contains 3 arrays of size 1440 (longitude) by 628 (latitude for range -78.375 to 78.375) by 4 (time of 0Z, 06Z, 12Z, 18Z). Two of the arrays are the U and V wind components in meters/second (m/s). Standard U and V coordinates apply, meaning the positive U is to the right and positive V is above the axis. U and V are relative to true north. CCMP winds are expressed using the oceanographic convention, meaning a wind blowing toward the Northeast has a positive U component and a positive V component. The third array in the file is the number of observations (nobs) used to derive the wind components. A nobs value of 0.0 means that the wind vector for that grid cell is very close to the wind vector from the background field because no satellite or moored buoy wind data were available to directly influence the analyzed vector wind.

CCMP V2.0级-3.5(L3.5)风可用作NetCDF-4数据文件。每月L3.5每月数据文件包含3个大小1440(经度)乘以628(范围为-78.375到78.375)(以日历月的中间为中心)。前两个阵列是米/秒(M / s)的矢量平均U和V风组件。第三个阵列包含每个位置的标量平均风速W.注意,在具有基本上随时间变化的风向的区域中,W可以远高于矢量平均部件U和V的大小。

A fill value of -9999.0 is used for any grid cell without any data. This should rarely happen. Longitude is given in degrees East from 0.125 to 359.875 and latitude is given in degrees North with negative values representing southern locations. While this is referred to as a global wind product, the extent of the data is -79 degrees to 79 degrees latitude. The time in the file is given as hours since midnight on Jan 1, 1987.

The netCDF file contains CF 1.6-compliant self-describing metadata. The JPL metadata compliance checker was used to assess compliance. The RSS CCMP V2.0 data set is distributed as L3.0 daily and L3.5 monthly files. The V1.1 CCMP data set available from PO.DAAC also contained L2.5 (vectors on satellite data) and L3.5 pentad data products. However, RSS has chosen to not distribute the L2.5 or L3.5 pentad data products at this time.

缺失数据

There are gaps within these data. There are 11 days scattered between May and December of 1988 and 14 days in January through July 1989 that do not appear on our FTP server

在此时间段内,F08是输入数据集的唯一运行卫星。缺少的日子是因为当天卫星收集了很少或没有数据。

在未来的重新处理中,我们可能会包括这些文件以完成完整性,但CCMP风领域本质上仅仅是ERA-INT背景,除了浮标附近的微小差异。

Read Routines / Data Access

The CCMP netCDF4 files can be explored using tools such asPanoply或者ncBrowse。Matlab, IDL, and Python have built-in routines for reading netCDF files. We have provided a sample read routine in Python. The routine will plot and display the data for an example file. CCMP data files can be obtained from RSS byftphttp

File names have the structure CCMP_Wind_Analysis_YYYYMMDD_V02.0_L3.0_RSS.nc where YYYY is the 4-digit year, MM the month and DD the day-of-month. The files are stored in v02.0/Yyyyy/Mmm/ directory structure.

Browse Images / Graphic Maps

The following movies loop through the full 28 years of data.

CCMP Wind Speed Animation

CCMP风速异常动画

Product Details

Product

Cross-Calibrated Multi-Platform Ocean Winds

Version

2.0

Spatial Coverage

Region: Global
Northernmost Latitude: 80 degrees
最南端的纬度:-80度
Westernmost Longitude: 0 degrees
Easternmost Longitude: 360 degrees

颞覆盖范围 1987-Jul-10 to 2016-May-30
Spatial Resolution

0.25度(纬度)x 0.25度(经度)

Temporal Resolution 6小时
Latency <6个月滞后(每年更新两次)

Input Data

平台/传感器/数据版本

AQUA / AMSR-E V7.0
GCOM-W1 / AMSR2 V7.2
TRMM / TMI V7.1
GPM / GMI V8.1
QUIKSCAT / SEAWINDS V4.0 (Ku-2011)
METOP-A / ASCAT V2.1
DMSP-F08 / SSM/I V7.0
DMSP-F10 / SSM/I V7.0
DMSP-F11 / SSM / I V7.0
DMSP-F13 / SSM/I V7.0
DMSP-F14 / SSM/I V7.0
DMSP-F15 / SSM / I V7.0
DMSP-F16 / SSMIS V7.0
DMSP-F17 / SSMIS V7.0
科里奥利/温莎v7.0.1

Data Format NetCDF-4, CF-1.6 compliant
File Size 每个文件约25 MB
Parameter 海面矢量风在10米高
Parameter Range 0到50米/秒
Unit of Measurement meters/second
接触 support@remss.com
数据提供者 万博体育app网页注册

Known Issues / Data Caveats

The following information should be taken into consideration when using this data product:

  • Users should not consider these winds suitable for studying global trends。While the winds are derived from consistently processed satellite data suitable for climate study, the act of assimilating the model data into an analysis product potentially introduces spurious trends that may exist in the background wind field. These CCMP V2.0 winds may, however, be suitable for studying regional trends and patterns.
  • 在研究高风区域时应使用小心。We have noted differences between satellite data and the CCMP winds at high wind speeds (>25 m/s), where the background model wind is known to underestimate wind events. Since the VAM method attempts to find a consistent wind field solution somewhere between the satellite-observed high wind events and the lower model winds for those same events, CCMP, as a wind analysis product, will inevitably be lower than the satellite data indicates. Note, wind events of this magnitude tend to be infrequent and geographically limited.
  • The V2.0 winds are different from the V1.1 winds。Users should not compare or mix the two products. Differences between the versions do exist and are related to the changes in the satellite data and background wind field. For example, the new Ku-2011 GMF QuikSCAT winds are much improved at high wind speeds resulting in lower CCMP V2.0 winds at speeds greater than 25 m/s when compared to the CCMP V1.1 winds.

相关数据

The或者iginal CCMP V1.1 FLK dataare available at the NASA Physical Oceanography DAAC (podaac.jpl.nasa.gov)

参考

阿特拉斯,R, R·n·霍夫曼j . Ardizzone s . m . Leidner, J. C. Jusem, D. K. Smith, D. Gombos, 2011: A cross-calibrated, multiplatform ocean surface wind velocity product for meteorological and oceanographic applications. Bull. Amer. Meteor. Soc., 92, 157-174. doi: 10.1175/2010BAMS2946.1

Atlas, R., R.N. Hoffman, S.C. Bloom, J.C. Jusem, and J. Ardizzone, 1996: A multiyear global surface wind velocity dataset using SSM/I wind observations. Bull. Amer. Meteor. Soc., 77, 5, 869-882.

Hoffman, R. N., M. Leidner, J. M. Henderson, R. Atlas, J. V. Ardizzone, and S. C. Bloom, 2003: A two-dimensional variational analysis method for NSCAT ambiguity removal: methodology, sensitivity, and tuning. Journal of Atmospheric & Oceanic Technology, 20, 585-605.

The original V1.1Cross-Calibrated Multi-Platform Ocean Surface Wind Vector Analyses User Guide(.pdf)可从jpl po.daac获得。

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。manbext万博官网请在纸质的确认部分中包含以下声明:

"CCMP Version-2.0 vector wind analyses are produced by Remote Sensing Systems. Data are available atwww.dj-hx.com。"

Data Set Citation

Wentz, F.J., J. Scott, R. Hoffman, M. Leidner, R. Atlas, J. Ardizzone, 2015: Remote Sensing Systems Cross-Calibrated Multi-Platform (CCMP) 6-hourly ocean vector wind analysis product on 0.25 deg grid, Version 2.0, [indicate date subset, if used]. Remote Sensing Systems, Santa Rosa, CA. Available online atwww.dj-hx.com/manbet客户端2.0万博吧measurements/ccmp.。[访问DD MMM YYYY]。*在括号中插入适当的信息。

Journal Reference

阿特拉斯,R, R·n·霍夫曼j . Ardizzone s . m . Leidner, J. C. Jusem, D. K. Smith, D. Gombos, 2011: A cross-calibrated, multiplatform ocean surface wind velocity product for meteorological and oceanographic applications. Bull. Amer. Meteor. Soc., 92, 157-174. doi: 10.1175/2010BAMS2946.1

MEARS,C. A.,Scott,J.,Vidz,F. J.,Ricciardulli,L.,Leidner,S. M.,Hoffman,R.,&Atlas,R。(2019)。交叉校准多平台(CCMP)海面风速数据集的近实时版本。地球物理研究杂志:海洋,124,6997-70万博网址是什么10。https://doi.org/10.1029/2019JC015367