The spatial distribution of soil moisture, especially the temporal variation at seasonal and interannual scales, is difficult for many land surface models （LSMs） to capture partly due to the deficiencies of the LSMs...The spatial distribution of soil moisture, especially the temporal variation at seasonal and interannual scales, is difficult for many land surface models （LSMs） to capture partly due to the deficiencies of the LSMs and the highly spatial variability of soil moisture, which makes it problematic to simulate the moisture for climate studies. However the soil moisture plays an important role in influencing the energy and hydrological cycles between the land and air, so it should be considered in land surface models. In this paper, a soil moisture simulation in China with a T213 resolution （about 0.5625°× 0.5625°） is compared to the observational data, and its relationship to precipitation is explored. The soil moisture distribution agrees roughly with the observations, and the soil moisture pattern reflects the variation and intensity of the precipitation. In particular, for the 1998 summer catastrophic floods along the Yangtze River, the soil moisture remains high in this region from July to August and represents the flood well. The seasonal cycle of soil moisture is roughly consistent with the observed data, which is a good calibration for the ground simulation capacity of the Atmosphere-Vegetation Interaction Model （AVIM） with respect to this tough problem for land surface models.展开更多
A land surface model driven by the continuous three-year observed meteorological data with a time interval of 30 minutes at the Tongyu station, a reference site of the Coordinated Enhanced Observing Period （CEOP）, w...A land surface model driven by the continuous three-year observed meteorological data with a time interval of 30 minutes at the Tongyu station, a reference site of the Coordinated Enhanced Observing Period （CEOP）, was used to evaluate the observation bias of soil moisture （SM） data and analyze the variation of SM at different time scales. The saline-alkaline soil of the grassland at the Tongyu site makes the measured SM too high, especially in boreal summer of 2003-05. The simulated annual mean SM has the lowest value in 2004 and its three-year variation corresponds to the change of precipitation, whereas the observation shows the increasing trend from 2003 to 2005. Compared to the variation range between -60% and 40% for the anomaly percentage of the simulated daily mean SM during May-October of 2004, the measured data show the higher values more than 40%. The magnitude of the variation trend of the observed daily mean SM in 2003 and 2005 is generally consistent with the simulation. The largest deficiency for the soil moisture observation of the grassland is the overestimated value in the drought year with less precipitation. The simulated monthly mean SM has the lowest value in March due to the large contribution of evaporation relative to precipitation and this phenomenon can not be reproduced in the observation.展开更多
A continuous 22-year simulation in Asia for the period of 1 January 1979 to 31 December 2000 was conducted using the Regional Integrated Environmental Model System (RIEMS 2.0) with NCEP Reanalysis Ⅱ data as the drivi...A continuous 22-year simulation in Asia for the period of 1 January 1979 to 31 December 2000 was conducted using the Regional Integrated Environmental Model System (RIEMS 2.0) with NCEP Reanalysis Ⅱ data as the driving fields. The model processes include surface physics state package (BATS 1e), a Grell cumulus parameterization, and a modified radiation package (CCM3) with the focus on the ability of the model to simulate the summer monsoon over East Asia. The analysis results show that (1) RIEMS reproduces well the spatial pattern and the seasonal cycle of surface temperature. When regionally averaged, the summer mean temperature biases are within 1―2℃. (2) For precipitation, the model reproduces well the spatial pattern, and temporal evolution of the East Asia summer monsoon rain belt, with steady phases separated by more rapid transitions, is reproduced. The rain belt simulated by RIEMS 2.0 is closer to observation than by RIEMS 1.0. (3) RIEMS 2.0 can reasonably reproduce the large-scale circulation.展开更多
Based on Atmosphere-Vegetation Interaction Model (AVIM), the magnitude and spatial distribution of terrestrial net primary productivity (NPP) in China is simu-lated during three different geological eras, Last Glacial...Based on Atmosphere-Vegetation Interaction Model (AVIM), the magnitude and spatial distribution of terrestrial net primary productivity (NPP) in China is simu-lated during three different geological eras, Last Glacial Maximum (LGM), Mid-Holocene (MH) and the present. The simulation shows that the glacial-interglacial variation of East Asian summer monsoon in China is the key factor af-fecting the NPP change. During the three eras, mean NPPs are 208 g/m2·a, 409 g/m2·a, and 355 g/m2·a. The total NPPs are 2.05 Pg/a, 3.89 Pg/a and 3.33 Pg/a, respectively. The ter-restrial NPP in China during warm-humid climate is larger than that during cold-arid eras, and the correlation analysis between NPP and climate factors suggests that temperature is the primary factor affecting the terrestrial NPP during 21 kaBP (LGM), and for 6 kaBP (MH) and the present the pri-mary factor is precipitation.展开更多
The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net prim...The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net primary production captured the distribution pattern in China better than MODIS and TRENDY data.The results for nitrogen deposition and biological nitrogen fixation show the good performance of the AVIM simulation compared with the CMIP6 and CABLE data,with a deposition rate>4 g N m-2yr-1in south China.The variation in the gross primary production and net primary production can be up to 300 and 200 g C m-2yr-1in south and southeast China,respectively,and there is a discrepancy between the AVIM and the data from MODIS and TRENDY.This shows the difficulty in simulating the carbon flux in a monsoon climate region and the importance of coupling the nitrogen–carbon fluxes.The standard deviation of nitrogen deposition and biological nitrogen fixation is simulated well by the AVIM and there is a large range in nitrogen deposition of 0.8–1.2 g N m-2yr-1in south China.The climatological mean of the fluxes performs better than the variation in the standard deviation and anomaly and this variation in the carbon–nitrogen flux is the key to decreasing bias in future modeling studies.展开更多
The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interact...The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interaction model (AVIM2). The results show that in the coming 100 a, for SRES B2 scenario and constant atmospheric CO2 concentration, the net primary productivity (NPP) of terrestrial ecosystem in China will be decreased slowly, and vegetation and soil carbon storage as well as net ecosystem productivity (NEP) will also be decreased. The carbon sink for China terrestrial ecosystem in the beginning of the 20th century will become totally a carbon source by the year of 2020, while for B2 scenario and changing atmospheric CO2 concentration, NPP for China will increase continuously from 2.94 GtC·a?1 by the end of the 20th century to 3.99 GtC·a?1 by the end of the 21st century, and vegetation and soil carbon storage will increase to 110.3 GtC. NEP in China will keep rising during the first and middle periods of the 21st century, and reach the peak around 2050s, then will decrease gradually and approach to zero by the end of the 21st century.展开更多
基金This work was supported by the Special Project of the China Meteorological Administration for Climate Change(Grant No.CCSF2005-1)various projects of the National Natural Science Foundation of China(Grant No.40205013 and 40005005).Thanks are given to Mr.Haibin Li for providing the in situ observations of soil moisture in China and for discussing them with us.
文摘The spatial distribution of soil moisture, especially the temporal variation at seasonal and interannual scales, is difficult for many land surface models （LSMs） to capture partly due to the deficiencies of the LSMs and the highly spatial variability of soil moisture, which makes it problematic to simulate the moisture for climate studies. However the soil moisture plays an important role in influencing the energy and hydrological cycles between the land and air, so it should be considered in land surface models. In this paper, a soil moisture simulation in China with a T213 resolution （about 0.5625°× 0.5625°） is compared to the observational data, and its relationship to precipitation is explored. The soil moisture distribution agrees roughly with the observations, and the soil moisture pattern reflects the variation and intensity of the precipitation. In particular, for the 1998 summer catastrophic floods along the Yangtze River, the soil moisture remains high in this region from July to August and represents the flood well. The seasonal cycle of soil moisture is roughly consistent with the observed data, which is a good calibration for the ground simulation capacity of the Atmosphere-Vegetation Interaction Model （AVIM） with respect to this tough problem for land surface models.
基金the National Basic Research Program of China (Grant No. 2006CB400500)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. IAP 07114)the National Natural Science Foundation of China (Grant Nos. 40605025, 40730106)
文摘A land surface model driven by the continuous three-year observed meteorological data with a time interval of 30 minutes at the Tongyu station, a reference site of the Coordinated Enhanced Observing Period （CEOP）, was used to evaluate the observation bias of soil moisture （SM） data and analyze the variation of SM at different time scales. The saline-alkaline soil of the grassland at the Tongyu site makes the measured SM too high, especially in boreal summer of 2003-05. The simulated annual mean SM has the lowest value in 2004 and its three-year variation corresponds to the change of precipitation, whereas the observation shows the increasing trend from 2003 to 2005. Compared to the variation range between -60% and 40% for the anomaly percentage of the simulated daily mean SM during May-October of 2004, the measured data show the higher values more than 40%. The magnitude of the variation trend of the observed daily mean SM in 2003 and 2005 is generally consistent with the simulation. The largest deficiency for the soil moisture observation of the grassland is the overestimated value in the drought year with less precipitation. The simulated monthly mean SM has the lowest value in March due to the large contribution of evaporation relative to precipitation and this phenomenon can not be reproduced in the observation.
基金Supported by the National Basic Research Program of China (Grant Nos. 2006CB400506 and 2009CB421100)International Cooperation Program for Science and Technology (Grant No. 2006DFB919201)Knowledge Innovation Project of Chinese Academy of Sciences (Grant Nos. KZ CX2-YW-Q11-03 and IAP07211)
文摘A continuous 22-year simulation in Asia for the period of 1 January 1979 to 31 December 2000 was conducted using the Regional Integrated Environmental Model System (RIEMS 2.0) with NCEP Reanalysis Ⅱ data as the driving fields. The model processes include surface physics state package (BATS 1e), a Grell cumulus parameterization, and a modified radiation package (CCM3) with the focus on the ability of the model to simulate the summer monsoon over East Asia. The analysis results show that (1) RIEMS reproduces well the spatial pattern and the seasonal cycle of surface temperature. When regionally averaged, the summer mean temperature biases are within 1―2℃. (2) For precipitation, the model reproduces well the spatial pattern, and temporal evolution of the East Asia summer monsoon rain belt, with steady phases separated by more rapid transitions, is reproduced. The rain belt simulated by RIEMS 2.0 is closer to observation than by RIEMS 1.0. (3) RIEMS 2.0 can reasonably reproduce the large-scale circulation.
基金supported by the key project of the National Natural Science Foundation of China(NSFC),“The development and application of a regional integrated environmental model system of two-way coupled vegetation and atmosphere”(Grant No.40231006)by National Basic Science Project(Grant No.G1999043408).
文摘Based on Atmosphere-Vegetation Interaction Model (AVIM), the magnitude and spatial distribution of terrestrial net primary productivity (NPP) in China is simu-lated during three different geological eras, Last Glacial Maximum (LGM), Mid-Holocene (MH) and the present. The simulation shows that the glacial-interglacial variation of East Asian summer monsoon in China is the key factor af-fecting the NPP change. During the three eras, mean NPPs are 208 g/m2·a, 409 g/m2·a, and 355 g/m2·a. The total NPPs are 2.05 Pg/a, 3.89 Pg/a and 3.33 Pg/a, respectively. The ter-restrial NPP in China during warm-humid climate is larger than that during cold-arid eras, and the correlation analysis between NPP and climate factors suggests that temperature is the primary factor affecting the terrestrial NPP during 21 kaBP (LGM), and for 6 kaBP (MH) and the present the pri-mary factor is precipitation.
基金jointly supported by the project of the National Key R&D Program of China grant No. 2018YFA0606004the National Natural Science Foundation of China grant Nos.41630532 and 41975112。
文摘The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net primary production captured the distribution pattern in China better than MODIS and TRENDY data.The results for nitrogen deposition and biological nitrogen fixation show the good performance of the AVIM simulation compared with the CMIP6 and CABLE data,with a deposition rate>4 g N m-2yr-1in south China.The variation in the gross primary production and net primary production can be up to 300 and 200 g C m-2yr-1in south and southeast China,respectively,and there is a discrepancy between the AVIM and the data from MODIS and TRENDY.This shows the difficulty in simulating the carbon flux in a monsoon climate region and the importance of coupling the nitrogen–carbon fluxes.The standard deviation of nitrogen deposition and biological nitrogen fixation is simulated well by the AVIM and there is a large range in nitrogen deposition of 0.8–1.2 g N m-2yr-1in south China.The climatological mean of the fluxes performs better than the variation in the standard deviation and anomaly and this variation in the carbon–nitrogen flux is the key to decreasing bias in future modeling studies.
基金the Basic Research Program of China (Grant No. 2002CB412500)the National Natural Science Foundation of China (Grant No. 30590384)
文摘The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interaction model (AVIM2). The results show that in the coming 100 a, for SRES B2 scenario and constant atmospheric CO2 concentration, the net primary productivity (NPP) of terrestrial ecosystem in China will be decreased slowly, and vegetation and soil carbon storage as well as net ecosystem productivity (NEP) will also be decreased. The carbon sink for China terrestrial ecosystem in the beginning of the 20th century will become totally a carbon source by the year of 2020, while for B2 scenario and changing atmospheric CO2 concentration, NPP for China will increase continuously from 2.94 GtC·a?1 by the end of the 20th century to 3.99 GtC·a?1 by the end of the 21st century, and vegetation and soil carbon storage will increase to 110.3 GtC. NEP in China will keep rising during the first and middle periods of the 21st century, and reach the peak around 2050s, then will decrease gradually and approach to zero by the end of the 21st century.
