scholarly journals Long‐term precipitation and stream discharge records at seven forested experimental watersheds along a latitudinal transect in Japan: Jozankei, Kamabuchi, Takaragawa, Tsukuba, Tatsunokuchi‐yama, Kahoku and Sarukawa

2021 ◽  
Vol 35 (10) ◽  
Author(s):  
Takanori Shimizu ◽  
Koji Tamai ◽  
Ikuhiro Hosoda ◽  
Shoji Noguchi ◽  
Yuji Kominami ◽  
...  
Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Terri Cook

Scientific insights from the Agricultural Research Service’s long-term study sites underpin dozens of models and research methods that guide global land management and conservation practices.


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1775
Author(s):  
Jozsef Szilagyi

Watershed-scale annual evapotranspiration (ET) is routinely estimated by a simplified water balance as the difference in catchment precipitation (P) and stream discharge (Q). With recent developments in ET estimation by the calibration-free generalized complementary relationship, the water balance equation is employed to estimate watershed/basin P at an annual scale as ET + Q on the United States (US) Geological Survey’s Hydrologic Unit Code (HUC) 2- and 6-level watersheds over the 1979–2015 period. On the HUC2 level, mean annual PRISM P was estimated with a correlation coefficient (R) of 0.99, relative bias (RB) of zero, root-mean-squared-error (RMSE) of 54 mm yr−1, ratio of standard deviations (RS) of 1.08, and Nash–Sutcliffe efficiency (NSE) of 0.98. On the HUC6 level, R, RS, and NSE hardly changed, RB remained zero, while RMSE increased to 90 mm yr−1. Even the long-term linear trend values were found to be fairly consistent between observed and estimated values with R = 0.97 (0.81), RMSE = 0.63 (1.63) mm yr−1, RS = 0.99 (1.05), NSE = 0.92 (0.59) on the HUC2 and HUC6 (in parentheses) levels. This calibration-free water-balance method demonstrates that annual watershed precipitation can be estimated with an acceptable accuracy from standard atmospheric/radiation and stream discharge data.


1988 ◽  
Vol 34 (116) ◽  
pp. 121-127 ◽  
Author(s):  
Douglas R. MacAyeal ◽  
Victor Barcilon

AbstractIce-stream discharge fluctuations constitute an independent means of forcing unsteady ice-shelf behavior, and their effect must be distinguished from those of oceanic and atmospheric climate to understand ice-shelf change. In addition, ice-stream-generated thickness anomalies may constitute a primary trigger of ice-rise formation in the absence of major sea-level fluctuations. Such triggering may maintain the current ice-rise population that, in turn, contributes to long-term ice-sheet stability. Here, we show that ice-stream-generated fluctuations of an ideal, two-dimensional ice shelf propagate along two characteristic trajectories. One trajectory permits instantaneous transmission of grounding-line velocity changes to all points down-stream. The other trajectory represents slow transmission of grounding-line thickness changes along Lagrangian particle paths.


1988 ◽  
Vol 34 (116) ◽  
pp. 121-127 ◽  
Author(s):  
Douglas R. MacAyeal ◽  
Victor Barcilon

AbstractIce-stream discharge fluctuations constitute an independent means of forcing unsteady ice-shelf behavior, and their effect must be distinguished from those of oceanic and atmospheric climate to understand ice-shelf change. In addition, ice-stream-generated thickness anomalies may constitute a primary trigger of ice-rise formation in the absence of major sea-level fluctuations. Such triggering may maintain the current ice-rise population that, in turn, contributes to long-term ice-sheet stability. Here, we show that ice-stream-generated fluctuations of an ideal, two-dimensional ice shelf propagate along two characteristic trajectories. One trajectory permits instantaneous transmission of grounding-line velocity changes to all points down-stream. The other trajectory represents slow transmission of grounding-line thickness changes along Lagrangian particle paths.


2017 ◽  
Author(s):  
Marcos R. C. Cordeiro ◽  
Jason A. Vanrobaeys ◽  
Henry F. Wilson

Abstract. Lack of long-term datasets in fine temporal resolution hinders environmental studies and modelling efforts; to address this issue in the La Salle River watershed, in Canada, long-term weather (1990–2013), hydrometric (1990–2013 except years with no or poor data), and water chemistry (2009–2013) datasets were developed. The weather variables consisted of temperature, relative humidity, wind speed, solar radiation, and precipitation in an hourly time-step, which is required for physically-based modelling. The only hydrometric variable included in the dataset was stream discharge in a daily time-step, which is the usual time-frame for summarizing the results of long-term studies. The water chemistry data consisted of total nitrogen (TN), total dissolved nitrogen (TDN), total phosphorus (TP) and total dissolved phosphorus (TDP). Samples were collected weekly during the open water season at the same site as they hydrometric gauging station (05OG008) starting in August 2009 until October 2012 with some gaps (i.e. Fall 2011, Spring 2012, September 2012). In 2013 the frequency of sampling was increased to daily or sub-daily during high stream discharge and weekly during low stream discharge. An overview of the data indicates that values and trends are within ranges reported in the literature for the region. Mean annual, winter, and summer temperatures were 3.5 °C–10.7 °C and 17.2 °C, respectively. Annual relative humidity averaged 73.1 % but tended to be higher and more homogenous in cold seasons. Wind speed was very similar over the different seasons with annual average of 4.3 m/s. Solar radiation followed the typical curve reported for western Canada, with peak daily average values around 250 W/m2 in July. The precipitation records were mostly comprised of dry hours and the characteristic precipitation pattern of the Canadian Prairies with high frequency of small precipitation events as observed, with 75.3 % of the hourly precipitation being equal or less than 2 mm/h. The hydrometric characteristics of the dataset were also typical of the Canadian Prairies; the average peak discharge over the entire period was larger in April (2.3 m3/s) due to large amounts of snowmelt runoff. The average concentrations of TN, TDN, TP and TDP of 1.54, 1.35, 0.56, and 0.49 mg/L, respectively, were in agreement with values found in previous studies at the same location. The datasets for weather (https://doi.org/10.23684/ODI-2017-00957), discharge (https://doi.org/10.23684/ODI-2017-00959) and water chemistry (https://doi.org/10.23684/ODI-2017-00958) are accessible through the Government of Canada's Open Data portal (http://open.canada.ca).


2001 ◽  
Vol 37 (11) ◽  
pp. 2857-2861 ◽  
Author(s):  
Frederick B. Pierson ◽  
Charles W. Slaughter ◽  
Zane K. Cram

Environments ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 19
Author(s):  
Daniel J. Hornbach

Climate change is likely to have large impacts on freshwater biodiversity and ecosystem function, especially in cold-water streams. Ecosystem metabolism is affected by water temperature and discharge, both of which are expected to be affected by climate change and, thus, require long-term monitoring to assess alterations in stream function. This study examined ecosystem metabolism in two branches of a trout stream in Minnesota, USA over 3 years. One branch was warmer, allowing the examination of elevated temperature on metabolism. Dissolved oxygen levels were assessed every 10 min from spring through fall in 2017–2019. Gross primary production (GPP) was higher in the colder branch in all years. GPP in both branches was highest before leaf-out in the spring. Ecosystem respiration (ER) was greater in the warmer stream in two of three years. Both streams were heterotrophic in all years (net ecosystem production—NEP < 0). There were significant effects of temperature and light on GPP, ER, and NEP. Stream discharge had a significant impact on all GPP, ER, and NEP in the colder stream, but only on ER and NEP in the warmer stream. This study indicated that the impacts of temperature, light, and discharge differ among years, and, at least at the local scale, may not follow expected patterns.


1993 ◽  
Vol 24 (2-3) ◽  
pp. 65-78
Author(s):  
Edw. F. Chacho

Snowmelt runoff and total suspended solids were measured for two years on Glenn Creek, a small, second-order, subarctic stream located near Fairbanks, Alaska, within the Yukon-Tanana Uplands physiographic province. The stream drains a 2.25-km2 research watershed of which 70 % is underlain by permafrost. The two years of study represent very different snowmelt hydrographs due to differences in the snowpacks. In 1985, the snowpack was 180 % of the long-term average, while in 1988 it was only 56 % of the average. During both years, 60 % of the total snowmelt-season water yield had passed before a significant rate of solids yield was observed. Also in both years the peak in total suspended solids concentration lagged the stream discharge peak by three days. Diurnal fluctuations in discharge and total suspended solids concentrations are well-defined, including a peculiar occurrence of double diurnal peaks in the discharge hydrograph during portions of the snowmelt season. The diurnal fluctuations in solids concentration are shown to be consistent with water temperature fluctuations. In 1988, the percentage of organics in the total suspended solids was scattered from 0 % to 66 % during the snowmelt season.


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