Modern Average Global Sea-Surface Temperature, GCRP Subset

Information about the Modern Average Global Sea-Surface Temperature (USGS data
series DDS-10) Data Set archived at the USGS Global Change Research Program is
available via FTP:

"ftp://geochange.er.usgs.gov in /pub/magsst"

or via World Wide Web:
"http://pubs.usgs.gov/dds/dds10/magsst.html"

Directions on how to obtain the CD-ROM or access it on-line are made available
on the WWW site. The following information about the data set was provided by
the data center contact:

The purpose of this data set is to provide Paleoclimate researchers with a
tool for estimating the average seasonal variation in sea- surface temperature
(SST) through out the modern world ocean and for estimating the modern monthly
and weekly sea-surface temperature at any given oceanic location. It is
expected that these data will be compared with temperature estimates derived
from geological proxy measures such as faunal census analyses and stable
isotopic analyses. The results can then be used to constrain general
circulation models of climate change.

The data contained in this data set are derived from the NOAA Advanced Very
High Resolution Radiometer Multichannel Sea Surface Temperature data (AVHRR
MCSST), which are obtainable from the Distributed Active Archive Center at the
Jet Propulsion Laboratory (JPL) in Pasadena, Calif. The JPL tapes contain
weekly images of SST from October 1981 through December 1990 in nine regions of
the world ocean: North Atlantic, Eastern North Atlantic, South Atlantic,
Agulhas, Indian, Southeast Pacific, Southwest Pacific, Northeast Pacific, and
Northwest Pacific.

This data set represents the results of calculations carried out on the NOAA
data and also contains the source code of the programs that made the
calculations. The objective was to derive the average sea- surface temperature
of each month and week throughout the whole 10-year series, meaning, for
example, that data from January of each year would be averaged together. The
result is 12 monthly and 52 weekly images for each of the oceanic regions.
Averaging the images in this way tends to reduce the number of grid cells that
lack valid data and to suppress interannual variability.

As ancillary data, the ETOPO5 global gridded elevation and bathymetry data
(Edwards, 1989) were interpolated to the resolution of the SST data; the
interpolated topographic data are included. The images are provided in three
formats: a modified form of run-length encoding (MRLE), Graphics Interchange
Format (GIF), and Macintosh PICT format.

Also included in the data set are programs that can retrieve seasonal
temperature profiles at user-specified locations and that can decompress the
data files. These nongraphical SST retrieval programs are provided in versions
for UNIX, MS-DOS, and Macintosh computers. Graphical browse utilities are
included for users of UNIX with the X Window System, 80386-based PC's, and
Macintosh computers.

现存档于美国地质调查局（United States Geological Survey, USGS）全球变化研究项目的现代全球平均海表温度（USGS数据系列DDS-10）数据集相关信息，可通过文件传输协议（File Transfer Protocol, FTP）获取：地址为"ftp://geochange.er.usgs.gov"，路径为"/pub/magsst"；亦可通过万维网（World Wide Web）访问："http://pubs.usgs.gov/dds/dds10/magsst.html"。

万维网站点上提供了获取光盘版或在线访问该数据集的操作指南。以下数据集相关信息由数据中心联系人提供：

本数据集旨在为古气候研究人员提供工具，用于估算全球现代海洋各季节的海表温度（Sea Surface Temperature, SST）平均变化，以及任意海洋位置的现代月均、周均海表温度。预期可将本数据集与基于地质代用指标（如生物群落普查分析、稳定同位素分析）得到的温度估算结果进行比对，所得结果可用于约束气候变化的通用环流模型。

本数据集包含的数据源自美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）的先进甚高分辨率辐射计多通道海表温度数据（Advanced Very High Resolution Radiometer Multichannel Sea Surface Temperature, AVHRR MCSST），此类数据可从位于加利福尼亚州帕萨迪纳市的喷气推进实验室（Jet Propulsion Laboratory, JPL）分布式主动存档中心获取。JPL的磁带存储了1981年10月至1990年12月期间全球9个海洋区域的周级海表温度影像，分别为：北大西洋、东北大西洋、南大西洋、阿古拉斯海盆、印度洋、东南太平洋、西南太平洋、东北太平洋及西北太平洋。

本数据集包含对上述NOAA数据进行计算后的结果，同时附带了用于生成这些计算结果的程序源代码。本次计算的目标是推导整个10年序列中每个月和每周的平均海表温度，例如将每年1月的所有数据进行平均处理。最终成果为每个海洋区域对应12张月均影像与52张周均影像。通过此种影像平均方式，可减少缺失有效数据的网格单元数量，并抑制年际变异性。

作为辅助数据，ETOPO5全球网格化高程与水深数据（Edwards, 1989）被插值至海表温度数据的分辨率，插值后的地形数据已包含在本数据集中。数据集提供三种格式的影像文件：改进型游程编码（Modified Run-Length Encoding, MRLE）、图形交换格式（Graphics Interchange Format, GIF）及麦金塔（Macintosh）PICT格式。

本数据集还包含可在用户指定位置提取季节温度剖面的程序，以及用于解压缩数据文件的工具。这些非图形化海表温度提取程序提供了UNIX、微软磁盘操作系统（Microsoft Disk Operating System, MS-DOS）及麦金塔（Macintosh）计算机的适配版本。同时还为使用X窗口系统（X Window System）的UNIX用户、基于80386的个人计算机用户及麦金塔（Macintosh）计算机用户提供了图形化浏览工具。