ICOADS国际全球海-气综合数据集（1800-2020）

ICOADS（国际海洋-大气综合数据集）是3个世纪以来的海洋气象和表层海洋数据集，这些数据和产品分布于全球范围，源于不同的观测系统，主要是船测（商用，海军，研究）、浮标（系泊和漂流浮标）、沿海观测站、其他海洋平台，采样范围是全球性的，采样密度随日期和地理位置的不同而不同，地理位置与航线和海洋观测系统有关。这些观测系统涵盖了几百年来观测技术的变化，因此ICOADS可能是目前比较完整和全面的全球海-气综合数据集。包括海温、SLP、空气温度、风速、云量等22个变量和参数，这些变量都是独立观测的，同时又是物理相关的。这些数据除了质控，未经任何加工（如，未经时空上的平滑或插值）。ICOADS数据包括几种不同形式，具有不同的时间段、时间步长和网格分辨率。零散的观测数据可以追溯到1662年，但气候科学家最感兴趣的可能是每月的统计数据，这些统计数据包括2°×2°数据（1800年至近期）和1°×1°数据（1960年至近期）的统计数据，如，平均值、中位数、观测次数等。
具体来说，每个变量都分为“标准”（standard）和“增强”（enhanced）两部分产品，反映的是质量控制、混合数据的差异。“标准”产品用其气候数据的3.5σ（标准差）进行限制校订，观测数据仅限于船舶观测。“增强”产品则使用范围更广泛的4.5σ（标准差）进行校订，更好地描述极端气候事件。
优点：（1）几种气候变量的长时间序列；（2）相对于其他类似产品（如，NOAA ERSST; HadSLP2），本数据集提供了原始观测；（3）除了月平均值，还提供标准差、精确度、观测样本数。
一些不足：（1）除了一些基本质控，没进行校正（如，仪器、观测方式、船型等的变化），有研究表明，某些区域和时段存在虚假趋势。例如，风速的上升趋势、海温的上升趋势与观测方式、观测仪器的升级有关；（2）由于商业航运航线分布不均匀，某些地区和时期的数据覆盖率较低：北大西洋、南大西洋西部和印度洋北部的观测密度最高，早在1870年左右就有合理的观测范围。1946年前后的数据覆盖范围局限于北太平洋，1960年前后的观测主要覆盖于热带地区，南部海洋的采样一直很少。
ICOADS是多国合作产品。其中美国的贡献是国家海洋和大气管理局（NOAA），特别是其地球系统研究实验室（ESRL）、其国家环境信息中心（NCEI）和环境科学研究所合作研究（CIRES），与科罗拉多大学联合进行的，以及美国国家科学基金会的国家大气研究中心（NCAR）。

The International Comprehensive Ocean-Atmosphere Data Set (ICOADS) is a three-century-long record of marine meteorological and surface oceanographic data. These globally distributed data and products originate from diverse observing systems, primarily ship-based observations (commercial, naval, and research vessels), buoys (moored and drifting), coastal observatories, and other marine platforms. The sampling is global in coverage, with sampling densities varying across dates and geographic locations, which are correlated with shipping routes and marine observing networks. These observing systems span centuries of changes in observation technology, so ICOADS may represent one of the most complete and comprehensive global ocean-atmosphere integrated datasets available to date.

It includes 22 variables and parameters such as sea surface temperature (SST), sea level pressure (SLP), air temperature, wind speed, and cloud cover. All these variables are independently observed and physically interrelated. The data have undergone quality control (QC) but have not been subjected to any further processing, such as spatial-temporal smoothing or interpolation. ICOADS data are available in several different formats, with varying time periods, temporal resolutions, and grid resolutions. Sporadic observational records date back to 1662, but the monthly statistics that are of most interest to climate scientists include aggregates for 2°×2° grids (from 1800 to the present) and 1°×1° grids (from 1960 to the present), such as mean values, median values, and the number of observations.

Specifically, each variable is divided into two product sets: "standard" and "enhanced", which reflect differences in quality control and blended data processing. The "standard" product set is calibrated using a 3.5σ (standard deviation) threshold of its climate data, with observational data limited to ship-based measurements. The "enhanced" product set uses a wider 4.5σ threshold for calibration, which better characterizes extreme climate events.

Advantages: (1) Long time series of multiple climate variables; (2) Provides raw observational data compared to similar existing products such as NOAA ERSST and HadSLP2; (3) In addition to monthly mean values, it also provides standard deviations, precision metrics, and the number of observational samples.

Limitations: (1) Except for basic quality control, no corrections have been made for changes in instruments, observation methods, ship types, etc. Studies have shown that spurious trends exist in certain regions and time periods. For example, the upward trends in wind speed and sea surface temperature are associated with upgrades in observation methods and instruments; (2) Due to the uneven distribution of commercial shipping routes, data coverage is low in some regions and periods: the highest observation densities are found in the North Atlantic, western South Atlantic, and northern Indian Ocean, with reasonable observational coverage dating back to around 1870. Data coverage around 1946 was limited to the North Pacific, observations around 1960 were primarily concentrated in the tropical regions, and sampling in the Southern Ocean has remained sparse throughout.

ICOADS is a multinational collaborative product. The contributions from the United States come from the National Oceanic and Atmospheric Administration (NOAA), particularly its Earth System Research Laboratory (ESRL), National Centers for Environmental Information (NCEI), and the Cooperative Institute for Research in Environmental Sciences (CIRES) jointly operated with the University of Colorado, as well as the National Center for Atmospheric Research (NCAR) funded by the U.S. National Science Foundation.

搜集汇总

背景与挑战

背景概述

ICOADS国际全球海-气综合数据集（1800-2020）是一个覆盖全球海表的长期海洋气象数据集，包含海温、气压、风速等22个变量，源自船测、浮标等多种观测系统，提供原始观测数据并分为标准与增强产品，具有月时间分辨率和2°×2°或1°×1°空间分辨率。该数据集优点在于提供长时间序列和原始观测，但存在未校正仪器变化和数据覆盖率不均的不足，适用于非盈利研究用途。