Jiangsu Collaborative Innovation Center for Climate Change

Nanjing, China

Jiangsu Collaborative Innovation Center for Climate Change

Nanjing, China
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Li D.,CAS Institute of Atmospheric Physics | Li D.,University of Chinese Academy of Sciences | Zou L.,CAS Institute of Atmospheric Physics | Zou L.,Jiangsu Collaborative Innovation Center for Climate Change | And 3 more authors.
Climate Dynamics | Year: 2017

Extreme heat (EH) over North China (NC) is affected by both large scale circulations and local topography, and could be categorized into foehn favorable and no-foehn types. In this study, the performance of a regional coupled model in simulating EH over NC was examined. The effects of regional air–sea coupling were also investigated by comparing the results with the corresponding atmosphere-alone regional model. On foehn favorable (no-foehn) EH days, a barotropic cyclonic (anticyclonic) anomaly is located to the northeast (northwest) of NC, while anomalous northwesterlies (southeasterlies) prevail over NC in the lower troposphere. In the uncoupled simulation, barotropic anticyclonic bias occurs over China on both foehn favorable and no-foehn EH days, and the northwesterlies in the lower troposphere on foehn favorable EH days are not obvious. These biases are significantly reduced in the regional coupled simulation, especially on foehn favorable EH days with wind anomalies skill scores improving from 0.38 to 0.47, 0.47 to 0.61 and 0.38 to 0.56 for horizontal winds at 250, 500 and 850 hPa, respectively. Compared with the uncoupled simulation, the reproduction of the longitudinal position of Northwest Pacific subtropical high (NPSH) and the spatial pattern of the low-level monsoon flow over East Asia are improved in the coupled simulation. Therefore, the anticyclonic bias over China is obviously reduced, and the proportion of EH days characterized by anticyclonic anomaly is more appropriate. The improvements in the regional coupled model indicate that it is a promising choice for the future projection of EH over NC. © 2017 Springer-Verlag Berlin Heidelberg

Ma S.,Chinese Academy of Meteorological Sciences | Ma S.,CAS Institute of Atmospheric Physics | Ma S.,University of Chinese Academy of Sciences | Zhou T.,CAS Institute of Atmospheric Physics | And 4 more authors.
Journal of Climate | Year: 2017

The southeastern periphery of the Tibetan Plateau (SEPTP) was hit by an extraordinarily severe drought in the autumn of 2009. Overall, the SEPTP has been gripped by a sustained drought for six consecutive years. To better understand the physical causes of these types of severe and frequent droughts and thus to improve their prediction and enhance the ability to adapt, many research efforts have been devoted to the disastrous droughts in the SEPTP. Nonetheless, whether the likelihood and strength of the severe droughts in the SEPTP, such as that in the autumn of 2009, have been affected by anthropogenic climate change remains unknown. This study first identifies the atmospheric circulation regime responsible for the SEPTP droughts and then explores how human-induced climate change has affected the severe droughts in the SEPTP. It is found that the drought conditions in the SEPTP have been driven by the Indian-Pacific warm pool (IPWP) sea surface temperature (SST) through strengthening of the local Hadley circulation and anomalously cyclonic motion over the South China Sea. Ensemble simulations of climate models demonstrate a robust increase in the dry and warm meteorological conditions seen during the 2009 SEPTP autumn drought due to anthropogenic global warming.Given that warming is expected to continue into the future, these results suggest that it is likely that drought conditions will become more common in the SEPTP. © 2017 American Meteorological Society.

Zhang L.,Harbin Normal University | Jiang L.,Harbin Normal University | Zhang X.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhang X.,Jiangsu Collaborative Innovation Center for Climate Change
Journal of Geographical Sciences | Year: 2017

We initially estimated the cropland area at county level using local historical documents for the Songnen Plain (SNP) in the 1910s and 1930s. We then allocated this cropland area to grid cells with a size of 1 km × 1 km, using a range of cultivation possibilities from high to low; this was based on topography and minimum distances to rivers, settlements, and traffic lines. Cropland areas for the 1950s were obtained from the Land Use Map of Northeast China, and map vectorization was performed with ArcGIS technology. Cropland areas for the 1970s, 1980s, 1990s, 2000s, and 2010s were retrieved from Landsat images. We found that the cropland areas were 4.92 × 104 km2 and 7.60 × 104 km2, accounting for 22.8% and 35.2% of the total area of the SNP in the 1910s and 1930s, respectively, which increased to 13.14 × 104 km2, accounting for 60.9% in the 2010s. The cropland increased at a rate of 1.18 × 104 km2 per decade from the 1910s to 1970s while it was merely 0.285 × 104 km2 per decade from the 1970s to 2010s. From the 1910s to 1930s, new cultivation mainly occurred in the central SNP while, from the 1930s to 1970s, it was mainly over the western and northern parts. This spatially explicit reconstruction could be offered as primary data for studying the effects of changes in human-induced land cover based on climate change over the last century. © 2017, Institute of Geographic Science and Natural Resources Research (IGSNRR), Science China Press and Springer-Verlag GmbH Germany.

Huang X.,Peking University | Huang X.,Institute for Climate and Global Change Research | Huang X.,Nanjing University | Huang X.,Jiangsu Collaborative Innovation Center for Climate Change | And 5 more authors.
Journal of Climate | Year: 2015

The direct radiative effect (DRE) of multiple aerosol species [sulfate, nitrate, ammonium, black carbon (BC), organic carbon (OC), and mineral aerosol] and their spatiotemporal variations over China were investigated using a fully coupled meteorology-chemistry model [Weather Research and Forecasting (WRF) Model coupled with Chemistry (WRF-Chem)] for the entire year of 2006. This study made modifications to improve the model performance, including updating land surface parameters, improving the calculation of transition-metal-catalyzed oxidation of SO2, and adding heterogeneous reactions between mineral dust aerosol and acid gases. The modified model generally reproduced the magnitude, seasonal pattern, and spatial distribution of the measured meteorological conditions, concentrations of PM10 and its components, and aerosol optical depth (AOD), although some low biases existed in modeled aerosol concentrations. A diagnostic iteration method was used to estimate the overall DRE of aerosols and contributions from different components. At the land surface, the incident net radiation flux was reduced by 10.2 W m-2 over China. Aerosols significantly warmed the atmosphere with the national mean DRE of +10.8 W m-2. BC was the leading radiative heating component (+8.7 W m-2), followed by mineral aerosol (+1.1W m-2). At the top of the atmosphere (TOA), BC introduced the largest radiative perturbation (+4.5W m-2), followed by sulfate (-1.4W m-2). The overall perturbation of aerosols on radiation transfer is quite small over China, demonstrating the counterbalancing effect between scattering and adsorbing aerosols. AerosolDREat theTOAhad distinct seasonality, generally with a summer maximum and winter minimum, mainly determined by mass loadings, hygroscopic growth, and incident radiation flux. © 2015 American Meteorological Society.

Zhang N.,Nanjing University | Zhang N.,Jiangsu Collaborative Innovation Center for Climate Change | Gao Z.,CAS Institute of Atmospheric Physics | Liu Y.,Brookhaven National Laboratory | Li D.,Princeton University
Journal of Geophysical Research Atmospheres | Year: 2015

The critical bulk Richardson number (Ricr) is an important parameter in planetary boundary layer (PBL) parameterization schemes used in many climate models. This paper examines the sensitivity of a global climate model, the Beijing Climate Center atmospheric general circulation model, to Ricr. The results show that the simulated global average of PBL height increases nearly linearly with Ricr, with a change of about 114 m for a change of 0.5 in Ricr. The surface sensible (latent) heat flux decreases (increases) as Ricr increases. The influence of Ricr on surface air temperature and specific humidity is not significant. The increasing Ricr may affect the location of the Westerly Belt in the Southern Hemisphere. Further diagnosis reveals that changes in Ricr affect stratiform and convective precipitations differently. Increasing Ricr leads to an increase in the stratiform precipitation but a decrease in the convective precipitation. Significant changes of convective precipitation occur over the Intertropical Convergence Zone, while changes of stratiform precipitation mostly appear over arid land such as North Africa and Middle East. © 2015. American Geophysical Union. All Rights Reserved.

Sun R.,Nanjing University | Yuan H.,Nanjing University | Yuan H.,Jiangsu Collaborative Innovation Center for Climate Change | Liu X.,Anhui Agricultural University | Jiang X.,Nanjing University
Journal of Hydrology | Year: 2016

Satellite-gauge quantitative precipitation estimate (QPE) products may reduce the errors in near real-time satellite precipitation estimates by combining rain gauge data, which provides great potential to hydrometeorological applications. This study aims to comprehensively evaluate four of the latest satellite-gauge QPEs, including NASA's Tropical Rainfall Measuring Mission (TRMM) 3B42V7 product, NOAA's Climate Prediction Center (CPC) MORPHing technique (CMORPH) bias-corrected product (CMORPH CRT), CMORPH satellite-gauge merged product (CMORPH BLD) and CMORPH satellite-gauge merged product developed at the National Meteorological Information Center (NMIC) of the China Meteorological Administration (CMA) (CMORPH CMA). These four satellite-gauge QPEs are statistically evaluated over the Huaihe River basin during 2003-2012 and applied into the distributed Variable Infiltration Capacity (VIC) model to assess hydrologic utilities.Compared to the China Gauge-based Daily Precipitation Analysis (CGDPA) newly developed at CMA/NMIC, the four satellite-gauge QPEs generally depict the spatial distribution well, with the underestimation in the southern mountains and overestimation in the northern plain of the Huaihe River basin. Specifically, both TRMM and CMORPH CRT adopt simple gauge adjustment algorithms and exhibit relatively poor performance, with evidently deteriorated quality in winter. In contrast, the probability density function-optimal interpolation (PDF-OI) gauge adjustment procedure has been applied in CMORPH BLD and CMORPH CMA, resulting in higher quality and more stable performance. CMORPH CMA further benefits from a merged dense gauge observation network and outperforms the other QPEs with significant improvements in rainfall amount and spatial/temporal distributions. Due to the insufficient gauge observations in the merging process, CMORPH BLD features the similar error characteristics of CMORPH CRT with a positive bias of light precipitation and a negative bias of heavy precipitation, in contrast to the overall large overestimation by TRMM. The quality of QPEs directly impacts streamflow simulations, as the precipitation biases are propagated into simulated streamflow through interaction with hydrologic processes. The general streamflow pattern is well captured at multiple time scales by the simulations using the four satellite-gauge QPEs as the input forcing. CMORPH CRT shows the worst simulations in both long-term streamflow and extreme flood events, while CMORPH CMA forced streamflow simulations even outperform that forced by CGDPA. CMORPH CMA is able to reproduce the July 2003 flood event, while the other three QPEs fail to generate such extreme flood. Overall, CMORPH CMA shows great potential to improve the precipitation distribution and hydrometeorological simulations, and can serve as an alternative high quality QPE in China. © 2016 Elsevier B.V.

Guo Y.,Sun Yat Sen University | Wen Z.,Sun Yat Sen University | Wen Z.,Jiangsu Collaborative Innovation Center for Climate Change | Wu R.,CAS Institute of Atmospheric Physics
Journal of Climate | Year: 2016

The leadingmode of boreal spring precipitation variability over the tropical Pacific experienced a pronounced interdecadal change around the late 1990s. The pattern before 1998 features positive precipitation anomalies over the equatorial eastern Pacific (EP) with positive principle component years. The counterpart after 1998 exhibits a westward shift of the positive center to the equatorial central Pacific (CP). Observational evidence shows that this interdecadal change in the leading mode of precipitation variability is closely associated with a distinctive sea surface temperature (SST) anomaly pattern. The westward shift of the anomalous precipitation center after 1998 is in tandemwith a similar shift of maximumwarming from the EP to CP.Diagnostic analyses based on a linear equation of themixed layer temperature anomaly exhibit that an interdecadal enhancement of zonal advection (ZA) feedback process plays a vital role in the shift in the leading mode of both the tropical Pacific SST and the precipitation anomaly during spring. Moreover, the variability of the anomalous zonal current at the upper ocean dominates the ZA feedback change, while the mean zonal SST gradient associated with a La Niña-like pattern of the mean state only accounts for a relatively trivial proportion of the ZA feedback change. It was found that both the relatively rapid decaying of the SST anomalies in the EP and the La Niña-like mean state make it conceivable that the shift of the leading mode of the tropical precipitation anomaly only occurs in spring. In addition, the largest variance of the anomalous zonal current in spring might contribute to the unique interdecadal change in the tropical spring precipitation anomaly pattern. © 2016 American Meteorological Society.

Wang J.,Sun Yat Sen University | Wang J.,State University of New York at Stony Brook | Wen Z.,Sun Yat Sen University | Wen Z.,Chinese Academy of Meteorological Sciences | And 3 more authors.
Climate Dynamics | Year: 2016

A pronounced summer rainfall increase over southern China occurred around 1992/1993. In the present study, the impact of the boreal summer intraseasonal oscillation (BSISO) on this decadal increase is investigated through diagnostic analysis. It is found that the BSISO-induced rainfall increase accounts for approximately 17.4% of the observed decadal rainfall increase, with a primary part coming from changes in the rainfall pattern associated with phases 3–5 of the BSISO. A further analysis reveals that changes in rainfall pattern over southern China are mainly ascribed to changes in spatial structure of anomalous convection associated with interdecadal change in BSISO tracks. Apart from significant influence of changes in BSISO tracks, changes in the frequency of individual active BSISO phases also have considerable influence on the interdecadal change in summer rainfall over southern China. Based on our analysis, the increase in absolute and relative frequency of occurrence of phases 1 and 8, coupled with their corresponding rainfall pattern, makes a positive contribution to the increase in southern China summer rainfall. The interdecadal change in the BSISO tracks and the frequency of active BSISO phases is likely related to coherent changes in atmospheric circulation and sea surface temperature over the Indian Ocean and the western Pacific. © 2016 Springer-Verlag Berlin Heidelberg

Zhang H.,Sun Yat Sen University | Wen Z.,Sun Yat Sen University | Wen Z.,Jiangsu Collaborative Innovation Center for Climate Change | Wu R.,CAS Institute of Atmospheric Physics | And 2 more authors.
Climate Dynamics | Year: 2016

Previous studies have revealed inter-decadal changes in the East Asian summer monsoon (EASM) that occurred around the late 1970s and early 1990s, respectively. The present study compares characteristics of these two changes and analyzes plausible influences of the South Indian Ocean (SIO) sea surface temperature (SST) change. The two changes share pronounced common features, characterized by an equivalent barotropic circulation anomaly over northern East Asia and a meridional vertical overturning circulation over the tropical region. Meanwhile, they display some distinct characteristics, especially over the tropics. The circumfluent anomalies are more robust for the first change than for the second one. Related amplitude asymmetry is partly attributed to a weakening trend in the EASM. Moreover, SST change in the SIO, featuring a decadal warming since the 1980s and a cooling after 1993, may contribute to both of these inter-decadal changes. Cold SST anomaly induces anomalous mid-tropospheric descent over the western SIO and ascent extending from the eastern SIO to western Australia and over the equatorial Indian Ocean. The accompanying upper-tropospheric divergent flows from western Australia and equatorial Indian Ocean to the Philippines lead to anomalous descent and an anomalous lower-tropospheric anticyclone over the South China Sea–Philippines. Warm SST anomaly induces opposite changes in above regions. The possible influence of SST anomaly in the SIO is further confirmed by numerical experiments. © 2016 Springer-Verlag Berlin Heidelberg

Zou X.,National Climate Center | Ren F.,Chinese Academy of Meteorological Sciences | Ren F.,Jiangsu Collaborative Innovation Center for Climate Change
Advances in Atmospheric Sciences | Year: 2015

A new technique for identifying regional climate events, the Objective Identification Technique for Regional Extreme Events (OITREE), was applied to investigate the characteristics of regional heavy rainfall events in China during the period 1961–2012. In total, 373 regional heavy rainfall events (RHREs) were identified during the past 52 years. The East Asian summer monsoon (EASM) had an important influence on the annual variations of China’s RHRE activities, with a significant relationship between the intensity of the RHREs and the intensity of the Mei-yu. Although the increase in the frequency of those RHREs was not significant, China experienced more severe and extreme regional rainfall events in the 1990s. The middle and lower reaches of the Yangtze River and the northern part of South China were the regions in the country most susceptible to extreme precipitation events. Some stations showed significant increasing trends in the southern part of the middle and lower reaches of the Yangtze River and the northern part of South China, while parts of North China, regions between Guangxi and Guangdong, and northern Sichuan showed decreasing trends in the accumulated intensity of RHREs. The spatial distribution of the linear trends of events’ accumulated intensity displayed a similar so-called “southern flooding and northern drought” pattern over eastern China in recent decades. © 2015, Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.

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