Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in e...Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in eastern North America, were selected to explore relationship between the northward distribution of temperate tree species and climatic factors. For each species, more than 30 sites at their north limits of distribution were obtained from their distribution maps, and 11 climatic indices at the north limits were computed. The standardized standard deviation (SD) method, which compares the magnitude of variance of climatic indices, was used to detect which climatic parameter was the most important for explaining northward distribution of these species. We presume that the climatic parameter that has the smallest variance at the north limit would be assigned as the dominant climatic factor for limiting the distribution of this species. The results derived from the standardized SD method indicated that the SD value of warmth index (WI) and/or annual biotemperature (ABT) were the smallest among the 11 climatic indices. Since both WI and ABT represent growing season temperature, it suggested that growing season temperature was the most important climatic factor for explaining the northward distribution of these temperate tree species. The relationships between several climatic indices, WI, coldness index (CI), annual precipitation (AP), annual range of temperature (ART) and humid/arid index were also analyzed. As a result, at the north limits of all these species, both WI and CI decreased with an increase of AP, and CI increased with an increase of ART. Besides growing season temperature, precipitation and climatic continentality also have influence on the northward distribution of the temperate trees in eastern North America.展开更多
In this study,the temporal and spatial variations of observed global oceanic precipitation during 1979-2010 are investigated.It is found that the global trend in precipitation during this period varies at a rate of 1....In this study,the temporal and spatial variations of observed global oceanic precipitation during 1979-2010 are investigated.It is found that the global trend in precipitation during this period varies at a rate of 1.5％/K of surface warming while the rate is 6.6％/K during 2006-2010.The precipitation is highly correlated with Sea Surface Temperature （SST） in both the temporal and the spatial patterns since the strong 1997-98 E1 Ni（n）o event.Considering the distributions of precipitation and SST,seven oceanic regions are classified and presented using the observed Global Precipitation Climatology Project （GPCP） data and Extended Reconstructed Sea Surface Temperatures,version 3 （ERSST.v3） data.Further examining the mechanisms of the classified oceanic precipitation regions is conducted using the Tropical Rainfall Measuring Mission （TRMM） satellite,GFDL-ESM-2G model precipitation and SST data and Hadley Center sea ice and SST version 1 （HadISST1） data.More than 85％ of global oceanic precipitations are controlled by either one or both of the warmer-get-wetter mechanism and wet-get-wetter mechanism.It is estimated that a 0.5 SST signal-to-noise ratio,representing the trend of SST time series to the standard deviation,is a criterion to distinguish the mechanism of a region.When the SST ratio is larger than 0.5,the precipitation of this region is controlled by the warmer-get-wetter mechanism.SST,rather than the humidity,is the pivotal factor.On the other hand,when the SST ratio is less than 0.5,the precipitation is controlled by the wet-get-wetter mechanism.The SST variability is a significant factor contributing to the precipitation variation.展开更多
文摘Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in eastern North America, were selected to explore relationship between the northward distribution of temperate tree species and climatic factors. For each species, more than 30 sites at their north limits of distribution were obtained from their distribution maps, and 11 climatic indices at the north limits were computed. The standardized standard deviation (SD) method, which compares the magnitude of variance of climatic indices, was used to detect which climatic parameter was the most important for explaining northward distribution of these species. We presume that the climatic parameter that has the smallest variance at the north limit would be assigned as the dominant climatic factor for limiting the distribution of this species. The results derived from the standardized SD method indicated that the SD value of warmth index (WI) and/or annual biotemperature (ABT) were the smallest among the 11 climatic indices. Since both WI and ABT represent growing season temperature, it suggested that growing season temperature was the most important climatic factor for explaining the northward distribution of these temperate tree species. The relationships between several climatic indices, WI, coldness index (CI), annual precipitation (AP), annual range of temperature (ART) and humid/arid index were also analyzed. As a result, at the north limits of all these species, both WI and CI decreased with an increase of AP, and CI increased with an increase of ART. Besides growing season temperature, precipitation and climatic continentality also have influence on the northward distribution of the temperate trees in eastern North America.
基金supported by the National Basic Research Program of China (2012CB955603)the Natural Science Foundation of China (41076115)Basic Scientific Research Operating Expenses of Ocean University of China
文摘In this study,the temporal and spatial variations of observed global oceanic precipitation during 1979-2010 are investigated.It is found that the global trend in precipitation during this period varies at a rate of 1.5％/K of surface warming while the rate is 6.6％/K during 2006-2010.The precipitation is highly correlated with Sea Surface Temperature （SST） in both the temporal and the spatial patterns since the strong 1997-98 E1 Ni（n）o event.Considering the distributions of precipitation and SST,seven oceanic regions are classified and presented using the observed Global Precipitation Climatology Project （GPCP） data and Extended Reconstructed Sea Surface Temperatures,version 3 （ERSST.v3） data.Further examining the mechanisms of the classified oceanic precipitation regions is conducted using the Tropical Rainfall Measuring Mission （TRMM） satellite,GFDL-ESM-2G model precipitation and SST data and Hadley Center sea ice and SST version 1 （HadISST1） data.More than 85％ of global oceanic precipitations are controlled by either one or both of the warmer-get-wetter mechanism and wet-get-wetter mechanism.It is estimated that a 0.5 SST signal-to-noise ratio,representing the trend of SST time series to the standard deviation,is a criterion to distinguish the mechanism of a region.When the SST ratio is larger than 0.5,the precipitation of this region is controlled by the warmer-get-wetter mechanism.SST,rather than the humidity,is the pivotal factor.On the other hand,when the SST ratio is less than 0.5,the precipitation is controlled by the wet-get-wetter mechanism.The SST variability is a significant factor contributing to the precipitation variation.
