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Yingying Chen
,
Kun Yang
,
Degang Zhou
,
Jun Qin
, and
Xiaofeng Guo

1. Introduction Arid and semiarid regions are an important portion of the global land surface. Many studies have indicated that desertification is increasing as a result of climatic change and human activities ( Puigdefabregas 1995 ; Warren 1996 ). The arid and semiarid region of northwestern China has experienced significant environmental changes within the last half century ( Ma and Fu 2006 ). Thus, it is crucial to understand the land–atmosphere interactions and to predict the variations of

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Shaobo Sun
,
Baozhang Chen
,
Quanqin Shao
,
Jing Chen
,
Jiyuan Liu
,
Xue-jun Zhang
,
Huifang Zhang
, and
Xiaofeng Lin

1. Introduction Evapotranspiration is the process where water is lost from the land surface to the atmosphere, including liquid water evaporation from various land surfaces, transpiration from plants, and sublimation of ice and snow. It is a key variable that links water, energy, and carbon cycles and plays a critical role in both the climate system and the hydrological cycle ( Chen and Coops 2009 ; Vinukollu et al. 2011 ; Wang et al. 2015 ). More than 60% of global land surface precipitation

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Xuelong Chen
,
Zhongbo Su
,
Yaoming Ma
,
James Cleverly
, and
Michael Liddell

1. Introduction Land surface temperature (LST), as a key variable at the land–atmosphere interface, may be derived from satellite sensor systems to provide global coverage ( Li et al. 2013 ). Remote sensing LST usage is growing within the fields of meteorology and climatology ( Tomlinson et al. 2011 ) and in studying urban heat island effects ( Imhoff et al. 2010 ). LST obtained by satellite remote sensing provides information with sufficient spatial resolution and global coverage to reveal new

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Rolf H. Reichle
,
Q. Liu
,
Randal D. Koster
,
Clara S. Draper
,
Sarith P. P. Mahanama
, and
Gary S. Partyka

1. Introduction Retrospective analysis (reanalysis) data products provide global, subdaily estimates of atmospheric and land surface conditions across several decades. Such products are based on the assimilation of a large amount of in situ and remote sensing observations into an atmospheric general circulation model (AGCM) and are among the most widely used datasets in Earth science. The recent Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2; Gelaro et al

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J. W. Yan
,
J. Y. Liu
,
B. Z. Chen
,
M. Feng
,
S. F. Fang
,
G. Xu
,
H. F. Zhang
,
M. L. Che
,
W. Liang
,
Y. F. Hu
,
W. H. Kuang
, and
H. M. Wang

1. Introduction As one of the principal physical processes in the land–atmosphere interaction system ( Zhang et al. 2003 ), land surface energy exchange is restricted by the climate system, but it also imposes strong feedbacks on the climate system ( Claussen et al. 2001 ). Energy exchange between land and the atmosphere is mainly determined by sensible heat flux ( H ), latent heat flux (LE), and net radiation (NR) ( Falge et al. 2005 ). Investigating the spatiotemporal changes in individual

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Aihui Wang
,
Xubin Zeng
,
Samuel S. P. Shen
,
Qing-Cun Zeng
, and
Robert E. Dickinson

1. Introduction Hydrological cycling between the atmosphere, vegetation, and soil plays an important role in land surface processes. Understanding its variability and relationship to atmospheric processes on various time scales will help better understand the impact of soil moisture on weather and climate and better manage water resources. One of the important aspects of the surface hydrological cycle is how the land surface components (soil moisture, evapotranspiration, and runoff) respond to

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Kevin Gallo
,
Robert Hale
,
Dan Tarpley
, and
Yunyue Yu

1. Introduction Land surface temperature (LST) is a key variable in determination of the land surface energy budget and is thus often assimilated into land surface models ( Rodell et al. 2004 ). LST (as soil or vegetation canopy temperature) is also used in models of vegetation stress (e.g., Jackson et al. 1981 ; Moran et al. 1994 ; Anderson et al. 2007 ). When observed over multiple years, LST can also be assessed for climatic trends (e.g., Jin 2004 ). Because of the relatively small

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Andrea Manrique-Suñén
,
Annika Nordbo
,
Gianpaolo Balsamo
,
Anton Beljaars
, and
Ivan Mammarella

1. Introduction With the resolution of numerical weather prediction models constrained by computational cost, a single grid box may span a wide variety of surface types. The subgrid-scale land surface heterogeneity must be parameterized in the surface scheme so that the land characteristics are accounted for in the model. Two alternative approaches are normally used to represent different surface types within a grid box. The first one combines the surface types to calculate effective parameters

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Fanglin Yang
,
Kenneth Mitchell
,
Yu-Tai Hou
,
Yongjiu Dai
,
Xubin Zeng
,
Zhuo Wang
, and
Xin-Zhong Liang

and improve the parameterizations of the solar zenith angle (SZA)–albedo relationship for climate and weather forecast models. Land surface albedos over both bare soil and plant canopies have a strong dependence on solar zenith angle and the surface characteristics. Since the surface types change considerably from place to place and throughout a growing season, it is a formidable problem to develop different schemes to model the dependence of surface albedo on SZA for different surface types

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Stefano Materia
,
Paul A. Dirmeyer
,
Zhichang Guo
,
Andrea Alessandri
, and
Antonio Navarra

1. Introduction In recent years, the important role played by the land surface in the global climate system has been recognized ( Koster et al. 2006 ), and increasingly sophisticated land surface schemes (LSSs) have been developed for general circulation models (GCMs; e.g., Bonan et al. 2002 ; Alessandri et al. 2007 ). Not only is an accurate simulation of the land surface state crucial for the skill of seasonal and weather forecasts ( Ferranti and Viterbo 2006 ; Fischer et al. 2007

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