With the popularity of the automatic precipitation gauges in national weather stations,testing their performance and adjusting their measurements are top priorities. Additionally,because different climatic conditions ...With the popularity of the automatic precipitation gauges in national weather stations,testing their performance and adjusting their measurements are top priorities. Additionally,because different climatic conditions may have different effects on the performance of the precipitation gauges, it is also necessary to test the gauges in different areas. This study mainly analyzed precipitation measurements from the single-Altershielded TRwS204 automatic weighing gauge(TRwS_(SA)) relative to the adjusted manual measurements(reference precipitation) from the Chinese standard precipitation gauge in a doublefence wind shield(CSPG_(DF)) in the Hulu watershed in the Qilian Mountains, China. The measurements were compared over the period from August 2014 to July2017, and the transfer function derived from the work by Kochendorfer et al.(2017 a) for correcting windinduced losses was applied to the TRwS_(SA) measurements. The results show that the average loss of TRwS_(SA) measurements relative to the reference precipitation decreased from 0.55 mm(10.7%) to 0.51 mm(9.9%) for rainfall events, from 0.35 mm(8.5%)to 0.22 mm(5.3%) for sleet events, and from 0.49 mm(18.9%) to 0.33 mm(12.7%) for snowfall events after adjustment. The uncorrected large biases of TRwS_(SA) measurements are considered to be mainly caused by specific errors of TRwS_(SA), different gauge orifice area and random errors. These types of errors must be considered when comparing precipitation measurements for different gauge types, especially in the mountains.展开更多
The Cross River watershed was disturbed by historic logging activity during the past century, but under the management of the USDA (United States Department of Agriculture) Forest Service, the area has mostly recove...The Cross River watershed was disturbed by historic logging activity during the past century, but under the management of the USDA (United States Department of Agriculture) Forest Service, the area has mostly recovered from ecological disturbance. Today a new threat is being imposed by climate change; changes affect not only the temperature but also more extreme wind and rain In 2012, a mega-storm event passed through the north shore region of Lake Superior overwhelming many watersheds with excessive rain and runoff. As part of a Cross River study for the Forest Service, pre- and post-event hydrologic adjustment of the Cross River watershed were captured. Samples were collected for δD and δ18O during April, July, and September to estimate HRT (hydraulic residence time) using the stable isotopes of hydrogen and oxygen, The results showed that water collected throughout the watershed shifted toward the signature of the mega-event precipitation signature, then slowly diffused with new precipitation and fractionation processes that resumed into the summer and fall.展开更多
基金supported primarily by the National Basic Research Program of China (2013CBA01806)the National Natural Sciences Foundation of China (41671029, 41690141, 41401040 and 41501040)
文摘With the popularity of the automatic precipitation gauges in national weather stations,testing their performance and adjusting their measurements are top priorities. Additionally,because different climatic conditions may have different effects on the performance of the precipitation gauges, it is also necessary to test the gauges in different areas. This study mainly analyzed precipitation measurements from the single-Altershielded TRwS204 automatic weighing gauge(TRwS_(SA)) relative to the adjusted manual measurements(reference precipitation) from the Chinese standard precipitation gauge in a doublefence wind shield(CSPG_(DF)) in the Hulu watershed in the Qilian Mountains, China. The measurements were compared over the period from August 2014 to July2017, and the transfer function derived from the work by Kochendorfer et al.(2017 a) for correcting windinduced losses was applied to the TRwS_(SA) measurements. The results show that the average loss of TRwS_(SA) measurements relative to the reference precipitation decreased from 0.55 mm(10.7%) to 0.51 mm(9.9%) for rainfall events, from 0.35 mm(8.5%)to 0.22 mm(5.3%) for sleet events, and from 0.49 mm(18.9%) to 0.33 mm(12.7%) for snowfall events after adjustment. The uncorrected large biases of TRwS_(SA) measurements are considered to be mainly caused by specific errors of TRwS_(SA), different gauge orifice area and random errors. These types of errors must be considered when comparing precipitation measurements for different gauge types, especially in the mountains.
文摘The Cross River watershed was disturbed by historic logging activity during the past century, but under the management of the USDA (United States Department of Agriculture) Forest Service, the area has mostly recovered from ecological disturbance. Today a new threat is being imposed by climate change; changes affect not only the temperature but also more extreme wind and rain In 2012, a mega-storm event passed through the north shore region of Lake Superior overwhelming many watersheds with excessive rain and runoff. As part of a Cross River study for the Forest Service, pre- and post-event hydrologic adjustment of the Cross River watershed were captured. Samples were collected for δD and δ18O during April, July, and September to estimate HRT (hydraulic residence time) using the stable isotopes of hydrogen and oxygen, The results showed that water collected throughout the watershed shifted toward the signature of the mega-event precipitation signature, then slowly diffused with new precipitation and fractionation processes that resumed into the summer and fall.