Snow is an important environmental variable in headwater systems that controls hydrological processes such as streamflow, groundwater recharge, and evapotran- spiration. These processes will be affected by both the am...Snow is an important environmental variable in headwater systems that controls hydrological processes such as streamflow, groundwater recharge, and evapotran- spiration. These processes will be affected by both the amount of snow available for melt and the rate at which it melts. Snow water equivalent （SWE） and snowmelt are known to vary within complex subalpine terrain due to terrain and canopy influences. This study assesses this variability during the melt season using ground penetrating radar to survey multiple plots in northwestern Colorado near a snow telemetry （SNOTEL） station. The plots include south aspect and flat aspect slopes with open, coniferous （subalpine fir, Abies lasiocarpa and engelman spruce, Picea engelmanii）, and deciduous （aspen, popu- lous tremuooides） canopy cover. Results show the high variability for both SWE and loss of SWE during spring snowmelt in 2014. The coefficient of variation for SWE tended to increase with time during snowmelt whereas loss of SWE remained similar. Correlation lengths for SWE were between two and five meters with melt having correlation lengths between two and four meters. The SNOTEL station regularly measured higher SWE values relative to the survey plots but was able to reasonably capture the overall mean loss of SWE during melt. Ground Penetrating Radar methods can improve future investiga- tions with the advantage of non-destructive sampling and the ability to estimate depth, density, and SWE.展开更多
Even if two implementations of a protocol pass the conformance testing,it cannot guarantee that they can interoperate properly;so direct testing of interoperation is considered indispensable.During the interoperabilit...Even if two implementations of a protocol pass the conformance testing,it cannot guarantee that they can interoperate properly;so direct testing of interoperation is considered indispensable.During the interoperability testing,a minimal number of test sequences are expected to check as many as possible implementation errors.By using minimal-complete-coverage criterion,the test sequence generation based on digraph can produce more effective test sequences.展开更多
文摘Snow is an important environmental variable in headwater systems that controls hydrological processes such as streamflow, groundwater recharge, and evapotran- spiration. These processes will be affected by both the amount of snow available for melt and the rate at which it melts. Snow water equivalent （SWE） and snowmelt are known to vary within complex subalpine terrain due to terrain and canopy influences. This study assesses this variability during the melt season using ground penetrating radar to survey multiple plots in northwestern Colorado near a snow telemetry （SNOTEL） station. The plots include south aspect and flat aspect slopes with open, coniferous （subalpine fir, Abies lasiocarpa and engelman spruce, Picea engelmanii）, and deciduous （aspen, popu- lous tremuooides） canopy cover. Results show the high variability for both SWE and loss of SWE during spring snowmelt in 2014. The coefficient of variation for SWE tended to increase with time during snowmelt whereas loss of SWE remained similar. Correlation lengths for SWE were between two and five meters with melt having correlation lengths between two and four meters. The SNOTEL station regularly measured higher SWE values relative to the survey plots but was able to reasonably capture the overall mean loss of SWE during melt. Ground Penetrating Radar methods can improve future investiga- tions with the advantage of non-destructive sampling and the ability to estimate depth, density, and SWE.
基金supported by the National Natural Science Foundation of China(Grant Nos.60241004,60602016 and 60602016)the National Basic Research Program of China(Grant No.2003CB314801)HUAWEI Foundation(No.YJCB2006044TS).
文摘Even if two implementations of a protocol pass the conformance testing,it cannot guarantee that they can interoperate properly;so direct testing of interoperation is considered indispensable.During the interoperability testing,a minimal number of test sequences are expected to check as many as possible implementation errors.By using minimal-complete-coverage criterion,the test sequence generation based on digraph can produce more effective test sequences.
