Search Results

You are looking at 1 - 10 of 12 items for :

  • The Global Energy and Water Cycle Experiment (GEWEX) x
  • All content x
Clear All
Xi Chen, Yongqin David Chen, and Zhicai Zhang

1. Introduction In the highly populated Huaihe River plain region in China ( Fig. 1 ), human activities, especially agriculture, influence the hydrological processes, and water resources management must focus on sustainability, tracked based on an accurate understanding of water distribution and fluxes. In other words, water storage in and movement among all dynamically linked reservoirs must be estimated in order to evaluate water availability caused by human impact. This task of modeling the

Full access
Xubin Zeng and Aihui Wang

–National Center for Atmospheric Research (NCEP–NCAR) reanalysis was used as the atmospheric forcing data, and CLM3 was run offline over the BDT tile for 20 yr by cycling the reanalysis data for the year 1998. While L t is as large as 7.4 in June, it decreases to 0.4 in February ( Fig. 3a ). In the standard CLM3, January net radiative flux ( R n ) of 0.7 W m −2 is partitioned into soil heat flux ( G ) of −3.3 W m −2 and latent (LH) and sensible (SH) heat fluxes of 16.7 and −12.7 W m −2 respectively ( Figs

Full access
Ana M. B. Nunes and John O. Roads

on account of the continuous interaction between the atmospheric and the land surface models. We examine here a climate analysis of the coupled land surface scheme response to this model-adjusted precipitation, focusing initially on the impact on the surface water budget terms. Because the continuous assimilation of the precipitation produces changes in the surface radiation fluxes by modifying the surface albedo and cloud distribution, which is directly related to the changes in the moisture

Full access
Binayak P. Mohanty and Jianting Zhu

1. Introduction Moisture flux across the land–atmosphere boundary (through infiltration, evaporation, and plant transpiration) is an important component of large-scale hydroclimatic processes. Predicting the mean flux rate for a remote sensing footprint or model grid/pixel is usually a primary concern in most practical soil–vegetation–atmospheric transfer (SVAT) models. One of the key land–atmosphere linkages is described by Koster et al. (2004) , whose results from a recent model

Full access
Yefim L. Kogan, Zena N. Kogan, and David B. Mechem

aircraft data from the Second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) field project to demonstrate that drizzle can be an important term in the water budget for marine stratocumulus. Austin et al. (1995) previously showed that local rain rates can be a significant fraction of the surface hydrologic balance—as much as 4–5 times larger than the local surface moisture flux. Drizzle is also an important component of the hydrologic cycle on climate scales, and an intercomparison of

Full access
Jinwon Kim and Hyun-Suk Kang

-shaped mountain. Pierrehumbert and Wyman (1985) found Fr c ≈ 0.67 for f = 0 and that Fr c varies with the Rossby number Ro when f ≠ 0 in a numerical study of stratified flows over a 2D barrier. Their results show that Fr c varies from 0.33 for Ro = 1 to 0.45 for Ro = 2. For a mesoscale mountain range, such as the Sierra Nevada whose cross-ridge length scale is 50–100 km, Ro is between 1 and 2 in the midlatitudes. On the basis of measured gravity wave momentum flux profiles, Kim and Mahrt (1992a

Full access
Xia Zhang, Shu Fen Sun, and Yongkang Xue

temperature, ice content, and unfrozen water content are in a delicate equilibrium state. A slight change in energy and mass balances will disturb the equilibrium of the three water phases in the soil, which in turn causes the release or absorption of latent heat and then a change in soil temperature. These changes would further alter the heat and water fluxes. All of these interactive effects, through the coupling of thermal and hydrological processes, are more prominent in the frozen zone with abrupt

Full access
Richard G. Lawford, John Roads, Dennis P. Lettenmaier, and Phillip Arkin

state of the surface as represented by soil moisture is critical in determining the heat and moisture fluxes to the atmosphere. Papers in the third section of this special issue deal with global and regional water budgets, which are also an integrating theme of GEWEX. This summary paper is intended to provide the reader with a broader perspective and understanding of GEWEX as well as a context for the detailed papers that follow. GEWEX is organized into three research domains: modeling and

Full access
Guoxiong Wu, Yimin Liu, Qiong Zhang, Anmin Duan, Tongmei Wang, Rijin Wan, Xin Liu, Weiping Li, Zaizhi Wang, and Xiaoyun Liang

caution. From 1995 to 1999 there was a China–Japan cooperation experiment of surface energy and water cycle over the TP. Six automatic meteorology stations (AMS) were installed at Lhasa (29°40′N, 91°08′E), Rikeze (29°15′N, 88°53′E), Lingzi (29°34′N, 94°28′E), Nagqu (31°29′N, 92°04′E), Gaize (32°09′N, 84°25′E), and Shiquanhe (32°30′N, 80°05′E). Based on these observations, the surface fluxes were calculated by Li et al. (2000 , 2001 ). Duan and Wu (2005) compared the surface sensible heat flux at

Full access
Song Yang, S-H. Yoo, R. Yang, K. E. Mitchell, H. van den Dool, and R. W. Higgins

2004 ). Soil moisture interacts with the overlying atmosphere through surface energy and water balances, and the amount of soil moisture strongly influences the degree of heat and moisture exchange between the land and the atmosphere ( Qu et al. 1998 ; Dirmeyer et al. 2000 ; Timbal et al. 2002 ; Gutowski et al. 2004 ; Zhu and Liang 2005 ). As pointed out by Dirmeyer et al. (1999) , soil moisture also determines the partitioning of land surface heat flux between sensible and latent components

Full access