Intercomparison of freshwater fluxes over ocean and investigations into water budget closure
Intercomparison of freshwater fluxes over ocean and investigations into water budget closure
复制标题
海洋淡水通量的比较和水预算闭合的调查
DOI：
10.5194/hess-2020-317
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发表时间：
2020
影响因子：
6.3
通讯作者：
F. Robertson
中科院分区：
文献类型：
--
作者：
Marloes Gutenstein;K. Fennig;M. Schröder;T. Trent;S. Bakan;J. Roberts;F. Robertson
抽象的。水循环组件提取算法的研究进展
卫星数据--如水汽总量(TCWV)、降水量
(P)、潜热通量和蒸发(E)--在以下方面取得了很大进展
过去30年。在目前的研究中，我们比较了六个最近的
基于卫星的检索算法和ERA5(欧洲中心
中期天气预报第五次重新分析)淡水通量(E−P)
关于全球和区域、季节和年际变化的数据
评估它们之间的对应程度。比较的数据集是
最近的、可免费获得的和有记录的气候数据记录(CDR)，开发
重点是时间序列的稳定性和同质性，而不是
瞬时准确度。我们研究的一个主要发现是全球海洋手段的共识
E−P数据集在星基数据的不确定范围内
数据。然而，在区域范围内，发现
卫星数据和ERA5。区域月平均值的回归分析
E、P和E−P与卫星数据的统计中值
总体(SEM)显示，尽管全球E
E−P数据之间的模式、偏差由P的差异主导
在全球各地。数据集之间的E−P差异是空间上的
不均匀的。我们观察到，对于ERA5，全球长期E-−P非常接近
0 mm d−1和那个
陆地和海洋的平均E−P在垂直方向上有很好的一致性
综合水汽通量散度(VIMD)和全球TCWV趋势。事实是
E和P在全球范围内是平衡的，这为调查提供了机会
E和P数据集之间的一致性。在海洋上，P(几乎)
如果水蒸气从海洋到陆地的净输送与E平衡
(以远洋VIMD表示，即∇⋅(VQ)Ocean)为
考虑到这一点。在每月的时间尺度上，线性回归
EOcean-∇⋅(VQ)Ocean与POcean
得出ERA5的R2=0.86，但卫星数据的R2值较小
布景。全球年度气候水循环组成部分总数(E、P、
E−P，以及从海洋到陆地的净运输量，反之亦然)
来自本研究中使用的数据集与先前的研究一致，
ERA5E和P占据范围的上部。两个都在海洋上
星载电子政务与星载电子政务的区别
基于卫星的P数据集大于E−P，并且这些数据仍然是
在观测到的全球水收支中最大的不确定性来源。我们的结论是，为了更好地了解全球水收支，
E和P数据集的质量需要提高，不确定因素
更加严格的量化。
Abstract. The development of algorithms for the retrieval of water cycle components from
satellite data – such as total column water vapor content (TCWV), precipitation
(P), latent heat flux, and evaporation (E) – has seen much progress in the
past 3 decades. In the present study, we compare six recent
satellite-based retrieval algorithms and ERA5 (the European Centre for
Medium-Range Weather Forecasts' fifth reanalysis) freshwater flux (E−P)
data regarding global and regional, seasonal and interannual variation to
assess the degree of correspondence among them. The compared data sets are
recent, freely available, and documented climate data records (CDRs), developed
with a focus on stability and homogeneity of the time series, as opposed to
instantaneous accuracy. One main finding of our study is the agreement of global ocean means of all
E−P data sets within the uncertainty ranges of satellite-based
data. Regionally, however, significant differences are found among the
satellite data and with ERA5. Regression analyses of regional monthly means of
E, P, and E−P against the statistical median of the satellite data
ensemble (SEM) show that, despite substantial differences in global E
patterns, deviations among E−P data are dominated by differences in P
throughout the globe. E−P differences among data sets are spatially
inhomogeneous. We observe that for ERA5 long-term global E−P is very close to
0 mm d−1 and that
there is good agreement between land and ocean mean E−P, vertically
integrated moisture flux divergence (VIMD), and global TCWV tendency. The fact
that E and P are balanced globally provides an opportunity to investigate
the consistency between E and P data sets. Over ocean, P (nearly)
balances with E if the net transport of water vapor from ocean to land
(approximated by over-ocean VIMD, i.e., ∇⋅(vq)ocean) is
taken into account. On a monthly timescale, linear regression of
Eocean-∇⋅(vq)ocean with Pocean
yields R2=0.86 for ERA5, but smaller R2 values are found for satellite data
sets. Global yearly climatological totals of water cycle components (E, P,
E−P, and net transport from ocean to land and vice versa) calculated
from the data sets used in this study are in agreement with previous studies,
with ERA5 E and P occupying the upper part of the range. Over ocean, both
the spread among satellite-based E and the difference between two
satellite-based P data sets are greater than E−P, and these remain the
largest sources of uncertainty within the observed global water budget. We conclude that, for a better understanding of the global water budget, the
quality of E and P data sets needs to be improved, and the uncertainties
more rigorously quantified.