There have been debates on the driving factors of C4 plant expansion, such as PCO2 decline in the late Micocene and warmer climate and precipitation at large-scale modern ecosystems. These disputes are mainly due to the lack of direct evidence and extensive data analysis. Here we use mass flora data to explore the driving factors of C4 distribution and divergent patterns for different C4 taxa a...

This paper investigates the influence of mean areal rainfall estimation errors on a specific case study: the use of lumped conceptual rainfall-runoff models to simulate the flood hydrographs of three small to medium-sized catchments of the upper Loire river. This area (3200 km2) is densely covered by an operational network of stream and rain gauges. It is frequently exposed to flash floods and ...

Thrce charts of the contiguous United States show (1) thc percentage of mean annual total precipitation contributed b j daily amounts of 0.50 i ~ ] . or greater, (2) the avcragc aiinual accuniulatioi~ of these daily amounts, and (3) the arcragc annual number of days having precipitation of 0.50 in. or greater.

The depth to carbonate nodular (Bk) horizon in soils (D in cm) is correlated with mean annual precipitation (P in mm), so that Bk horizons are deep in subhumid regions, but shallow in semiarid regions. Previous quantifications of this relationship are unchanged by this new compilation of 807 soils: P 5 137.24 1 6.45D 1 0.013D2, where R2 5 0.52, and standard error (S.E.) 5 6147 mm. In most North...

Monthly evapotranspiration (ET) rates (2000 to 2009) across Nebraska at about 1-km resolution were obtained by linear transformations of the MODIS (MODerate resolution Imaging Spectroradiometer) daytime surface temperature values with the help of the Priestley-Taylor equation and the complementary relationship of evaporation. For positive values of the mean annual precipitation and ET differenc...

A reconstructed land use/land cover change (LUCC) dataset was used with the Community Earth System Model (CESM) to conduct a climate sensitivity analysis over the past two millennia. Compared to a controlled experiment conducted with the CESM, the LUCC showed significant biogeophysical effects on global climate on multi-decadal to centennial time scales. The global annual mean temperature and p...

Temperature and precipitation have been separately reported to be the main factors affecting the Normalized Difference Vegetation Index (NDVI) in the Tibetan Plateau. The effects of the main climatic factors on the yearly maximum NDVI (MNDVI) in the Tibetan Plateau were examined on different scales. The result underscored the observation that both precipitation and temperature affect MNDVI base...

Stream¯ow simulations for 23 major river basins from the third-generation general circulation model (GCM) of the Canadian Centre for Climate Modelling and Analysis are assessed. Precipitation and runo€ data are used from the AMIP II simulation in which the GCM is integrated for a 17-yr period with speci®c sea surface temperatures and sea-ice concentrations. Compared to the observations, the com...