Goddard Satellite-Based Surface Turbulent Fluxes, 1x1 deg Yearly Climatology, Set1 and NCEP V2c (GSSTFYC) at GES DISC

These data are the Goddard Satellite-based Surface Turbulent Fluxes Version-2c Dataset recently produced through a MEaSURES funded project led by Dr. Chung-Lin Shie (UMBC/GEST, NASA/GSFC), converted to HDF-EOS5 format. The stewardship of this HDF-EOS5 dataset is part of the MEaSUREs project.

GSSTF version 2b (Shie et al. 2010, Shie et al. 2009) generally agreed better with available ship measurements obtained from several field experiments in 1999 than GSSTF2 (Chou et al. 2003) did in all three flux components, i.e., latent heat flux [LHF], sensible heat flux [SHF], and wind stress [WST] (Shie 2010a,b). GSSTF2b was also found favorable, particularly for LHF and SHF, in an intercomparison study that accessed eleven products of ocean surface turbulent fluxes, in which GSSTF2 and GSSTF2b were also included (Brunke et al. 2011).

However, a temporal trend appeared in the globally averaged LHF of GSSTF2b, particularly post year 2000. Shie (2010a,b) attributed the LHF trend to the trends originally found in the globally averaged SSM/I Tb's, i.e., Tb(19v), Tb(19h), Tb(22v) and Tb(37v), which were used to retrieve the GSSTF2b bottom-layer (the lowest atmospheric 500 meter layer) precipitable water [WB], then the surface specific humidity [Qa], and subsequently LHF. The SSM/I Tb's trends were recently found mainly due to the variations/trends of Earth incidence angle (EIA) in the SSM/I satellites (Hilburn and Shie 2011a,b). They have further developed an algorithm properly resolving the EIA problem and successfully reproducing the corrected Tb's by genuinely removing the "artifactitious" trends. An upgraded production of GSSTF2c (Shie et al. 2011) using the corrected Tb's has been completed very recently.

GSSTF2c shows a significant improvement in the resultant WB, and subsequently the retrieved LHF - the temporal trends of WB and LHF are greatly reduced after the proper adjustments/treatments in the SSM/I Tb's (Shie and Hilburn 2011). In closing, we believe that the insightful "Rice Cooker Theory" by Shie (2010a,b), i.e., "To produce a good and trustworthy 'output product' (delicious 'cooked rice') depends not only on a well-functioned 'model/algorithm' ('rice cooker'), but also on a genuine and reliable 'input data' ('raw rice') with good quality" should help us better comprehend the impact of the improved Tb on the subsequently retrieved LHF of GSSTF2c.

This is the Yearly Climatology product; data are projected to equidistant Grid that covers the globe at 1x1 degree cell size, resulting in data arrays of 360x180 size. Starting with Version 2c, there is only one set of Combined data, "Set1". The Monthly Climatology HDF-EOS5 file also contains one extra grid of NCEP Climatology, "NCEP". A finer resolution, 0.25 deg, of this product has been released as Version 3.

The yearly temporal and one-degree spatial resolution of the product can be used to examining climate variability at these scales. Oceanic evaporation contributes to the net fresh water input to the oceans and drives the upper ocean density structure and consequently the circulation of the oceans.

The short name for this product is GSSTFYC.

本数据集为近期由美国马里兰大学巴尔的摩县分校（UMBC/GEST）和NASA戈达德太空飞行中心（GSFC）的钟林·谢博士（Dr. Chung-Lin Shie）主持、MEaSURES项目资助的研究项目所生产的Goddard卫星地面湍流通量版2c数据集，该数据集已转换为HDF-EOS5格式。HDF-EOS5数据集的管理权亦属于MEaSURES项目。GSSTF版2b（Shie等，2010，Shie等，2009）在三个通量分量，即潜热通量（LHF）、感热通量（SHF）和风应力（WST）方面，普遍被认为与1999年多个现场实验获取的船舶测量值更为吻合，优于GSSTF2（Chou等，2003）。GSSTF2b在海洋表面湍流通量产品比较研究中亦表现出色，特别是在LHF和SHF方面，该研究评估了包括GSSTF2和GSSTF2b在内的十一项产品（Brunke等，2011）。然而，GSSTF2b的全球平均LHF呈现出了时间趋势，尤其在2000年之后。Shie（2010a,b）将LHF趋势归因于原本在全球平均SSM/I亮温（Tb）中发现的趋势，即Tb(19v)、Tb(19h)、Tb(22v)和Tb(37v)，这些亮温被用于提取GSSTF2b底层（最低500米大气层）降水量（WB），随后是表面比湿（Qa），进而是LHF。SSM/I亮温的趋势最近被发现主要归因于SSM/I卫星中地球入射角（EIA）的变化/趋势（Hilburn和Shie，2011a,b）。他们进一步开发了一种能够正确解决EIA问题的算法，并成功复制了经过校正的亮温，真实地去除了“人为的”趋势。利用校正后的亮温升级生产的GSSTF2c（Shie等，2011）最近已经完成。GSSTF2c在得到的WB方面表现出显著改进，随后检索出的LHF——WB和LHF的时间趋势在SSM/I亮温经过适当调整/处理后大幅降低（Shie和Hilburn，2011）。最后，我们认为Shie（2010a,b）提出的具有洞察力的“电饭煲理论”，即“要生产出优质、可靠的‘输出产品’（美味的‘煮熟的大米’），不仅需要一个功能完善的‘模型/算法’（‘电饭煲’），还需要具有良好质量的‘输入数据’（‘生米’）”，有助于我们更好地理解校正后的亮温对GSSTF2c随后检索出的LHF的影响。本产品为年度气候学产品；数据投影至等距网格，全球覆盖1x1度单元格大小，形成360x180大小的数据数组。从2c版开始，仅有一套综合数据集，“Set1”。月度气候学HDF-EOS5文件还包含一个额外的网格，即NCEP气候学，“NCEP”。该产品的更高分辨率版本，0.25度，已发布为3版。本产品的年度时间和一度的空间分辨率可用于考察这些尺度的气候变率。海洋蒸发对海洋净淡水输入有贡献，并驱动上层海洋密度结构，进而影响海洋环流。本产品的简称是GSSTFYC。