CCMP风矢量分析产品

版本2 CCMP风产品

该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)。V2 CCMP处理现在结合了Version-7 RSS辐射计风速,Quikscat和Acquat散射计风矢量,停泊浮标风数据和时代模型风场使用变分析方法(VAM),产生0.25度网格的四个地图矢量风。原始的CCMP产品(V1.1)最初由Bob Atlas和他的团队制作,并从美国宇航局的原因提供资金和措施方案。该原始措施产品从美国国家航空航天局的物理Oceanogr仍然可用吗aphy DAAC (podaac.jpl.nasa.gov). RSS has transitioned the CCMP processing code to run using our most up-to-date satellite data observations. All methodology remains the same as that used in the original CCMP product and most of the CCMP processing code is unchanged, with only minor alterations to compensate for the different operating systems and compilers.

Introduction

无间隙的海洋表面风数据高质量和高时和空间分辨率可用于各种目的,并且是研究影响大气和海洋的大规模海洋相互作用所必需的。海洋矢量风是动态的,在短时间内不断发展。这种特点使得全球包装,无间隙风场产生挑战,特别是在不到一天的时间刻度,而不是典型的风特征的空间尺度。准确的研究需要海洋万博网址是什么矢量风数据,足够长的时间段来解决风力诱导的模式,例如ElNiño-南部振荡(ENSO)和Madden-Julian振荡(MJO)。万博体育app网页注册遥感系统已投入多年的研究,以验证和交叉校准的被动和来自卫星的主动微波风检测。万博网址是什么

该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.该CCMP Version 2.0 (V2) data product described here is a continuation of the highly-used original CCMP product(V1.1可从美国宇航局JPL PO.DAAC提供),并在仔细的VAM开发的几十年里建立。两个同行评审出版物(Atlas等,1manbext万博官网996,Atlas等,2011)描述了原始的CCMP产品和(Hoffman等,2003)描述了VAM。本文档描述了从遥感系统提供的新型CCMP V2.0产品。万博体育app网页注册

原始的V1.1 CCMP产品是逐步处理的,多年来,使用加工时可用的卫星数据的小批次,因此,同化不一致地处理卫星风。也就是说,早期的V4至V6 RSS风用于早期生产年份,v7风在后几年的生产中。原始CCMP(v1.1)的资金于2012年结束,自2011年12月以来不会产生CCMP风。对CCMP产品的延续有相当大的需求,因此我们已将代码转换为RSS,以满足几个不同的目的目标:

  • Extend the product to the present time and continue processing into the future.
  • Reprocess using a consistent version of satellite data.
  • Add newly available sensors.
  • 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.

  • 该L3.0 CCMP V2.0 product contains four daily maps (00, 06, 12, and 18Z) of U and V vector wind components on a 0.25 degree global grid. The U and V components are relative to true north. The L3.0 data also includes maps of the number of observations (both satellite and in situ) that were analyzed at each location.
  • 该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.
  • CCMP V2.0产品的更新将每年大约两次,以便通过12月和6月完成处理。
  • 最新的更新发生于2018年3月,CCMP现已在2017年12月30日更新。

产品开发

该CCMP data set combines cross-calibrated satellite microwave winds and instrument observations using a Variational Analysis Method (VAM) to produce high-resolution (0.25 degree) gridded analyses. Satellite wind retrievals derived by Remote Sensing Systems from a number of satellite-borne passive and active microwave instruments are used. RSS intercalibrates radiometers at the brightness temperature level to within 0.2 degree Celsius, applying a refined sea-surface emissivity model and radiative transfer function to derive surface winds. The resulting wind retrievals are highly consistent between microwave radiometer instrument platforms, including1Manbetx ,1Manbetx ,AMSR,2018世界杯狗万滚球app ,2019新万博appmanbetⅩ , andGMI。RSS has also developed a geophysical model function for deriving wind speeds and directions from microwave scatterometers, includingQuikscat.and1mantbex 。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)时代临时再分析winds 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:

  • Use of uniform inputs and satellite retrievals, with all satellite winds produced using RSS Version-7 (or higher) Ocean Radiative Transfer Model (ORTM) and a consistent processing methodology.
  • Extension of the CCMP data set to July 2015 with plans to provide bi-annual extensions and updates to the dataset.
  • Addition of winds from new instruments: ASCAT Metop-A, AMSR2, and GMI.
  • Upgrade of the first-guess background wind field. Now using the 0.25-deg, 6-hourly ERA-Interim Reanalysis winds.
  • 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.),来自国家数据浮标中心(NDBC),以及来自渔业和海洋加拿大海洋学和科学数据分支(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.

数据产品格式

该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.

该CCMP V2.0 Level-3.5 (L3.5) winds are available as netCDF-4 data files. Each L3.5 monthly data file contains 3 arrays of size 1440 (longitude) by 628 (latitude for range -78.375 to 78.375) by 1 (time centered on the middle of the calendar month). The first two arrays are the vector-averaged U and V wind components in meters/second (m/s). The third array contains the scalar-averaged wind speed W for each location. Note that in regions with wind directions that vary substantially over time, W can be much higher than the magnitude of the vector-average components U and V.

填充值-9999.0用于任何网格单元而无需任何数据。这应该很少发生。经度以0.125至359.875以0.125给出,并且纬度以北方为代表南部地区的负值给出。虽然这被称为全球风产品,但数据的程度为-79度至79度纬度。自1987年1月1日以来,文件中的时间是几小时给出的。

该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.

Missing Data

这些数据中存在差距。在1988年5月至1988年12月至1989年1月至1989年7月之间存在11天,不会出现在我们的FTP服务器上

During this time period, F08 is the only operational satellite input into the dataset. Days that are missing are because there was either very little or no data collected by the satellite on that day.

In future reprocessing, we may include these files for completeness, but the CCMP wind field would essentially be just the ERA-Int background except for minor differences near buoys.

Read Routines / Data Access

该CCMP netCDF4 files can be explored using tools such asPanoplyorncBrowse。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 byFTP.andhttp

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

以下电影循环通过完整的28年数据。

CCMP风速动画

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
Southernmost Latitude: -80 degrees
最重要的是:0度
Easternmost Longitude: 360 degrees

Temporal Coverage 1987-Jul-10 to 2016-May-30
Spatial Resolution

0.25 degrees (Latitude) x 0.25 degrees (Longitude)

时间分辨率 6 Hour
Latency < 6 month lag (updated twice yearly)

输入数据

Platform / Sensor / Data Version

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
Coriolis / WindSat V7.0.1

数据格式 NetCDF-4, CF-1.6 compliant
文件大小 ~25 Mb per file
Parameter ocean surface vector winds at 10 meters height
Parameter Range 0到50米/秒
Unit of Measurement meters/second
Contact support@remss.com.
Data Provider 万博体育app网页注册

Known Issues / Data Caveats

使用此数据产品时应考虑以下信息:

  • 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.
  • Caution should be used when studying high wind regions。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.
  • 该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.

Related Data

原始CCMP V1.1 FLK数据可在美国宇航局物理海洋学DAAC(Podaac.jpl.nasa.gov)提供)

References

阿特拉斯,R.,R. N.Hoffman,J.Ardizzone,S. M.Leidner,J.C.Jusem,D.K.Smith,D.Gombos,2011:一个交叉校准的多层海洋表面风速产品,用于气象和海洋应用。公牛。amer。流星。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.

原版v1.1.Cross-Calibrated Multi-Platform Ocean Surface Wind Vector Analyses User Guide(.pdf) available from JPL PO.DAAC.

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:

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

数据集引文

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/measurements/ccmp。[Accessed dd mmm yyyy]. *Insert the appropriate information in the brackets.

Journal Reference

阿特拉斯,R.,R. N.Hoffman,J.Ardizzone,S. M.Leidner,J.C.Jusem,D.K.Smith,D.Gombos,2011:一个交叉校准的多层海洋表面风速产品,用于气象和海洋应用。公牛。amer。流星。SoC。,92,157-174。DOI:10.1175 / 2010BAMS2946.1

Mears, C. A., Scott, J., Wentz, F. J., Ricciardulli, L., Leidner, S. M., Hoffman, R., & Atlas, R. ( 2019). A Near Real Time Version of the Cross Calibrated Multiplatform (CCMP) Ocean Surface Wind Velocity Data Set. Journal of Geophysical Research: Oceans, 124, 6997– 7010. https://doi.org/10.1029/2019JC015367