Regional climate models are major tools for regional climate simulation and their output are mostly used for climate impact studies. Notes are reported from a series of numerical simulations of summer rainfall in Chin...Regional climate models are major tools for regional climate simulation and their output are mostly used for climate impact studies. Notes are reported from a series of numerical simulations of summer rainfall in China with a regional climate model. Domain sizes and running modes are major foci. The results reveal that the model in forecast mode driven by ＂perfect＂ boundaries could reasonably represent the inter-annual differences： heavy rainfall along the Yangtze River in 1998 and dry conditions in 1997. Model simulation in climate mode differs to a greater extent from observation than that in forecast mode. This may be due to the fact that in climate mode it departs further from the driving fields and relies more on internal model dynamical processes. A smaller domain in climate mode outperforms a larger one. Further development of model parameterizations including dynamic vegetation are encouraged in future studies.展开更多
This study was aimed to assess the impact of climate change on the water resource of Megech river catchment. In this study, large scale regional climate model (REMO) output was downscaled statistically to metrological...This study was aimed to assess the impact of climate change on the water resource of Megech river catchment. In this study, large scale regional climate model (REMO) output was downscaled statistically to metrological variables at a daily resolution using SDSM model version 5.11. We noticed that statistical downscaling smooth out the bias between REMO output and observed data. According to the projected climate data, the maximum temperature is likely to have an increasing trend +0.57°C while the minimum temperature shows a decreasing trends ﹣0.61°C. There is no clear trend for precipitation, both increasing and decreasing trend observed in the catchment. The HBV-Light hydrological model was successfully calibrated (1991-1995) and validated (1998-2000) using current climatic inputs and observed river flows. The overall performances of the model was good at monthly time scale both on calibration (NSE = 0.91) and validation (NSE = 0.86). Future discharge (2015-2050) was simulated using statistically downscaled 20 ensembles climate scenario data for both A1B and B1 scenarios. HBV-Light model simulation results showed a reduction of the peak discharge in August and September.展开更多
Qilian Mountains(QM)is an important ecological security barrier in China and has been significantly affected by climate change,it is therefore of great importance and necessity to project its future climate change usi...Qilian Mountains(QM)is an important ecological security barrier in China and has been significantly affected by climate change,it is therefore of great importance and necessity to project its future climate change using high-resolution climate models because of mountainous areas in the QM and relatively few targeted simulation analyses.In this study,we used the simulations of the regional climate model REMO with 25 km spatial resolution,driven by three different global climate models(MPI-ESM-MR,NorESM1-M,and HadGEM2-ES),to evaluate how annual and seasonal mean surface air temperature and precipitation in the QM are likely to change for three future periods(2011-2040,2041-2070,and 2071-2100)under two representative concentration pathways(RCP2.6 and RCP8.5).The REMO model,shows noticeable cold and wet biases compared to observations for the reference period(1971-2000)and air temperature simulation outperforms precipitation simulation.The REMO simulations exhibit a warm and wet centre around lake,indicating that the simulation are likely influenced by lake.Projections under RCP2.6 show regional warming reaching 1.74℃ during 2011-2100,characterized by an initial increase and a decrease afterwards.Under RCP8.5,air temperatures increase monotonously from 2011 to 2100,with a warming magnitude of 5.36℃ for 2071-2100 relative to 1971-2000.The overall change in regional-average annual precipitation is not evident during 2011-2100,with some increases or decreases in certain time periods.In the 2071-2100 both the strongest warming and precipitation increase are projected to occur in winter under both scenarios,while precipitation in summer and autumn is projected to decrease in the east of the QM for the three future periods.The results suggest that the QM is likely to experience drought conditions in warm seasons in the future,which could impact agricultural and livestock production.展开更多
To achieve stable and efficient nitrogen and phosphorus removal and to investigate the characteristics of the A/A SBR enriched with denitrifying phosphorus removal bacteria(DPB),the whole course of startup was studied...To achieve stable and efficient nitrogen and phosphorus removal and to investigate the characteristics of the A/A SBR enriched with denitrifying phosphorus removal bacteria(DPB),the whole course of startup was studied with two reactors operated in different mode.The reactor I was operated under anaerobic/settling/anoxic/settling mode,and the reactor II was operated under anaerobic/anoxic/settling mode.Differences between the two reactors in removal efficiency of COD,nitrogen and phosphorus were examined.The results indicated that efficient performance could be achieved in both reactors with different startup operation mode,while the phosphorus removal efficiency was improved sooner in reactor I than in reactor II,which suggested that reactor I would supply a more favorable condition for DPB proliferation.Meanwhile,it was observed that the amount of organic substrates consumption had a linear correlation to that of phosphorus release in anaerobic phase when DPB was accumulated in the A/A SBR denitrifying phosphorus removal system.展开更多
文摘Regional climate models are major tools for regional climate simulation and their output are mostly used for climate impact studies. Notes are reported from a series of numerical simulations of summer rainfall in China with a regional climate model. Domain sizes and running modes are major foci. The results reveal that the model in forecast mode driven by ＂perfect＂ boundaries could reasonably represent the inter-annual differences： heavy rainfall along the Yangtze River in 1998 and dry conditions in 1997. Model simulation in climate mode differs to a greater extent from observation than that in forecast mode. This may be due to the fact that in climate mode it departs further from the driving fields and relies more on internal model dynamical processes. A smaller domain in climate mode outperforms a larger one. Further development of model parameterizations including dynamic vegetation are encouraged in future studies.
文摘This study was aimed to assess the impact of climate change on the water resource of Megech river catchment. In this study, large scale regional climate model (REMO) output was downscaled statistically to metrological variables at a daily resolution using SDSM model version 5.11. We noticed that statistical downscaling smooth out the bias between REMO output and observed data. According to the projected climate data, the maximum temperature is likely to have an increasing trend +0.57°C while the minimum temperature shows a decreasing trends ﹣0.61°C. There is no clear trend for precipitation, both increasing and decreasing trend observed in the catchment. The HBV-Light hydrological model was successfully calibrated (1991-1995) and validated (1998-2000) using current climatic inputs and observed river flows. The overall performances of the model was good at monthly time scale both on calibration (NSE = 0.91) and validation (NSE = 0.86). Future discharge (2015-2050) was simulated using statistically downscaled 20 ensembles climate scenario data for both A1B and B1 scenarios. HBV-Light model simulation results showed a reduction of the peak discharge in August and September.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDA20100102)the National Key Research and Development Program of China(2019YFC0507401)+3 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0208)the National Natural Science Foundation of China(41771068)the Key Laboratory of Ecohydrology and Inland River Basin(KLEIRB-ZS-20-04)the Youth Innovation Promotion Association CAS(2018460).
文摘Qilian Mountains(QM)is an important ecological security barrier in China and has been significantly affected by climate change,it is therefore of great importance and necessity to project its future climate change using high-resolution climate models because of mountainous areas in the QM and relatively few targeted simulation analyses.In this study,we used the simulations of the regional climate model REMO with 25 km spatial resolution,driven by three different global climate models(MPI-ESM-MR,NorESM1-M,and HadGEM2-ES),to evaluate how annual and seasonal mean surface air temperature and precipitation in the QM are likely to change for three future periods(2011-2040,2041-2070,and 2071-2100)under two representative concentration pathways(RCP2.6 and RCP8.5).The REMO model,shows noticeable cold and wet biases compared to observations for the reference period(1971-2000)and air temperature simulation outperforms precipitation simulation.The REMO simulations exhibit a warm and wet centre around lake,indicating that the simulation are likely influenced by lake.Projections under RCP2.6 show regional warming reaching 1.74℃ during 2011-2100,characterized by an initial increase and a decrease afterwards.Under RCP8.5,air temperatures increase monotonously from 2011 to 2100,with a warming magnitude of 5.36℃ for 2071-2100 relative to 1971-2000.The overall change in regional-average annual precipitation is not evident during 2011-2100,with some increases or decreases in certain time periods.In the 2071-2100 both the strongest warming and precipitation increase are projected to occur in winter under both scenarios,while precipitation in summer and autumn is projected to decrease in the east of the QM for the three future periods.The results suggest that the QM is likely to experience drought conditions in warm seasons in the future,which could impact agricultural and livestock production.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50778052)Development Program for Outstanding Young Teachers in Harbin Institute of Technology(Grant No.NQQQ92324547)
文摘To achieve stable and efficient nitrogen and phosphorus removal and to investigate the characteristics of the A/A SBR enriched with denitrifying phosphorus removal bacteria(DPB),the whole course of startup was studied with two reactors operated in different mode.The reactor I was operated under anaerobic/settling/anoxic/settling mode,and the reactor II was operated under anaerobic/anoxic/settling mode.Differences between the two reactors in removal efficiency of COD,nitrogen and phosphorus were examined.The results indicated that efficient performance could be achieved in both reactors with different startup operation mode,while the phosphorus removal efficiency was improved sooner in reactor I than in reactor II,which suggested that reactor I would supply a more favorable condition for DPB proliferation.Meanwhile,it was observed that the amount of organic substrates consumption had a linear correlation to that of phosphorus release in anaerobic phase when DPB was accumulated in the A/A SBR denitrifying phosphorus removal system.
