CERES and GEO-Enhanced TOA, Within-Atmosphere and Surface Fluxes, Clouds and Aerosols Monthly Terra-Aqua-NOAA20 Edition4B

CER_SYN1deg-Month_Terra-Aqua-NOAA20_Edition4B is the Clouds and the Earth's Radiant Energy System (CERES) and geostationary (GEO)-Enhanced Top of Atmosphere (TOA), Within-Atmosphere, and Surface Fluxes, Clouds and Aerosols Monthly Terra-Aqua-NOAA20 Edition4A data product. Data was collected using the following instruments and platforms: Imaging Radiometers on Geostationary Satellites platform, CERES Flight Model 1 (FM1), CERES FM2, CERES Scanner, and MODIS on Terra; CERES FM3, CERES FM4, CERES Scanner, and MODIS on Aqua; and CERES FM6 and VIIRS on NOAA-20. Not all platforms are available for any particular data month. Data collection for this product is ongoing.

CERES Synoptic (SYN) 1 degree products provide CERES-observed temporally interpolated TOA radiative fluxes and coincident MODIS-derived cloud and aerosol properties and include geostationary-derived cloud properties and broadband fluxes that have been carefully normalized with CERES fluxes in order to maintain the CERES calibration. They also contain computed initial TOA, in-atmosphere, and surface fluxes and computed fluxes that have been adjusted or constrained to the CERES-observed TOA fluxes. The computed fluxes are produced using the Langley Fu-Liou radiative transfer model. Computations use MODIS , VIIRS, and geostationary satellite cloud properties along with atmospheric profiles provided by the NASA Global Modeling and Assimilation Office (GMAO). The adjustments to clouds and atmospheric properties are also provided. The computations are made for all-sky, clear-sky, pristine (clear-sky without aerosols), and all-sky without aerosol conditions. This product provides parameters on a three-hourly temporal resolution and 1°-regional spatial scales. Fluxes are provided for clear-sky and all-sky conditions in the longwave (LW), shortwave (SW), and window (WN) regions.

CERES SYN1deg products use 1-hourly radiances and cloud property data from geostationary (GEO) imagers to more accurately model variability between CERES observations. To use GEO data to enhance diurnal sampling, several steps are involved. First, GEO radiances are cross-calibrated with the MODIS imager using only data that is coincident in time and ray-matched in angle. Next, the GEO cloud retrievals are inferred from the calibrated GEO radiances. The GEO radiances are converted from narrowband to broadband using empirical regressions and then to broadband GEO TOA fluxes using Angular Distribution Models (ADMs) and directional models. To ensure GEO and CERES TOA fluxes are consistent, a normalization technique is used. Instantaneous matched gridded fluxes from CERES and GEO are regressed against one another over a month from 5°x5 ° latitude-longitude regions. The regression relation is then applied to all GEO fluxes to remove biases that depend upon cloud amount, solar and view zenith angles, and regional dependencies. The regional means are determined for 1° equal-angle grid boxes calculated by first interpolating each parameter for any missing times of the CERES/GEO observations to produce a complete 1-hourly time series for the month. Monthly means are calculated using the combination of observed and interpolated parameters from all days containing at least one CERES observation.

CERES is a key component of the Earth Observing System (EOS) program. The CERES instruments provide radiometric measurements of the Earth's atmosphere from three broadband channels. The CERES missions are a follow-on to the successful Earth Radiation Budget Experiment (ERBE) mission. The first CERES instrument, protoflight model (PFM), was launched on November 27, 1997 as part of the Tropical Rainfall Measuring Mission (TRMM). Two CERES instruments (FM1 and FM2) were launched into polar orbit on board the Earth Observing System (EOS) flagship Terra on December 18, 1999. Two additional CERES instruments (FM3 and FM4) were launched on board Earth Observing System (EOS) Aqua on May 4, 2002. The CERES FM5 instrument was launched on board the Suomi National Polar-orbiting Partnership (NPP) satellite on October 28, 2011. The newest CERES instrument (FM6) was launched on board the Joint Polar-Orbiting Satellite System 1 (JPSS-1) satellite, now called NOAA-20, on November 18, 2017.

CER_SYN1deg-Month_Terra-Aqua-NOAA20_Edition4B 是云和地球辐射能量系统 (Clouds and the Earth's Radiant Energy System, CERES) 与静止轨道 (Geostationary, GEO) 增强型顶层大气 (Top of Atmosphere, TOA)、大气内部及地表通量、云和气溶胶月尺度Terra-Aqua-NOAA20 第4A版数据集产品。本数据集的采集依托以下仪器与平台：静止轨道卫星平台搭载的成像辐射计、Terra卫星上的CERES飞行模型1 (FM1)、CERES FM2、CERES扫描仪与MODIS传感器；Aqua卫星上的CERES FM3、CERES FM4、CERES扫描仪与MODIS传感器；以及NOAA-20卫星上的CERES FM6与VIIRS传感器。需注意，并非所有平台均可在任意单个数据月中启用。本产品的数据采集工作仍在持续推进中。

CERES 合成 (Synoptic, SYN) 1度产品提供经CERES观测得到的时间插值TOA辐射通量，以及同步反演的MODIS云和气溶胶特性，同时包含静止轨道卫星反演的云特性与宽带通量——此类通量已通过与CERES通量进行严格归一化处理，以维持CERES的定标精度。产品还包含计算生成的初始TOA、大气内部及地表通量，以及经调整或约束至CERES观测TOA通量的计算通量。上述计算通量基于兰利-傅里叶-刘 (Langley Fu-Liou) 辐射传输模型生成，计算时采用MODIS、VIIRS及静止轨道卫星的云特性数据，辅以美国国家航空航天局 (National Aeronautics and Space Administration, NASA) 全球建模与同化办公室 (Global Modeling and Assimilation Office, GMAO) 提供的大气廓线数据。产品同时提供云和大气特性的调整结果。计算场景覆盖全天空、晴空、无气溶胶晴空（纯净晴空）以及无气溶胶全天空四种类型。本产品的时间分辨率为3小时，空间尺度为1°区域格网。通量数据按长波 (Longwave, LW)、短波 (Shortwave, SW) 及窗口 (Window, WN) 波段，分别提供晴空与全天空条件下的结果。

CERES SYN1deg 产品采用静止轨道成像仪的1小时辐射率与云特性数据，以更精准地模拟CERES观测间的时空变化特征。为利用静止轨道数据增强日采样密度，需执行以下处理流程：首先，仅选取时间同步且角度射线匹配的数据，将静止轨道辐射率与MODIS成像仪进行交叉定标；随后，基于定标后的静止轨道辐射率反演得到静止轨道云特性。通过经验回归方法将静止轨道辐射率从窄带转换为宽带，再结合角分布模型 (Angular Distribution Models) 与方向模型，将其转换为宽带静止轨道TOA通量。为确保静止轨道与CERES的TOA通量保持一致，采用归一化技术进行校正：将CERES与静止轨道的瞬时匹配格网通量，以5°×5°经纬度区域为单位，在一个月的时间范围内进行相互回归分析；随后将该回归关系应用于所有静止轨道通量，以消除依赖于云量、太阳与观测天顶角以及区域特性的系统偏差。1°等角格网的区域平均值计算方式为：首先对CERES与静止轨道观测中缺失时刻的参数进行插值，以生成该月完整的1小时时间序列；随后结合所有至少包含一次CERES观测的日期的实测与插值参数，计算得到月平均值。

CERES 是地球观测系统 (Earth Observing System, EOS) 计划的核心组成部分。CERES 仪器通过三个宽带通道对地球大气进行辐射测量。CERES 任务是成功的地球辐射预算实验 (Earth Radiation Budget Experiment, ERBE) 任务的后续项目。首台CERES仪器——原型飞行模型 (Protoflight Model, PFM)——作为热带降雨测量任务 (Tropical Rainfall Measuring Mission, TRMM) 的载荷之一，于1997年11月27日发射升空。两台CERES仪器(FM1与FM2)搭载于地球观测系统旗舰卫星Terra，于1999年12月18日进入极轨轨道。另外两台CERES仪器(FM3与FM4)搭载于地球观测系统Aqua卫星，于2002年5月4日发射升空。CERES FM5仪器于2011年10月28日搭载于Suomi国家极轨伙伴 (Suomi National Polar-orbiting Partnership, NPP) 卫星升空。最新的CERES仪器(FM6)于2017年11月18日搭载于联合极轨卫星系统1号 (Joint Polar-Orbiting Satellite System 1, JPSS-1) 卫星（现更名为NOAA-20）发射升空。