作者机构：
[Qin, Rui] Cent South Univ, Sch Geosci & Infophys, Changsha 410083, Peoples R China.;[Chen, Genliang; Qin, Rui] Second Survey & Mapping Inst Hunan Prov, Changsha 410009, Peoples R China.;[Qin, Rui] Cent South Univ, Key Lab Metallogen Predict Nonferrous Met & Geol, Changsha 410083, Peoples R China.;[Chen, Genliang] Minist Nat Resources, Key Lab Nat Resources Monitoring & Supervis South, Changsha 410009, Peoples R China.;[Zhang, Haibo] Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Peoples R China.
通讯机构：
[Luo Liu] G;Guangdong Province Key Laboratory for Land Use and Consolidation, South China Agricultural University, Guangzhou 510642, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
land surface temperature;time series;reconstruction;Kalman filter;GMS-5
摘要：
Satellite-derived environmental parameters play important roles in environmental research on global changes and regional resources. Atmosphere effects and sensor limitations often lead to data products that vary in quality. The main goal of time series data reconstruction is to use various statistical and numerical analysis methods and to stimulate changing seasonal or annual parameters, providing more complete data sets for correlational research. This paper aims to develop a time series reconstruction algorithm for LST based on data assimilation according to the current problems of unstable precision and unsatisfactory results, and the simplistic effects of evaluation methods while using remote sensing-derived LST data as the basic parameters and the daily LST data derived from the static meteorological satellite GMS-5 as the input data. The data assimilation system used the Kalman filter as the assimilation algorithm. A complete set of global refined LST time series data sets were obtained by constantly correcting the LST values according to the regional ground-based observations. This method was implemented using MATLAB software (version R2017a), and was applied and validated through partitioning using the principal elevation in the Beijing, Tianjin, and Hebei regions. The results show that the accuracy of the reconstructed LST data series improved significantly in terms of the mean and standard deviation. Better consistency was achieved between the variables obtained over a year from the reconstructed LST data and the ground observations from the LST data set.
期刊：
Open Geosciences,2021年13(1):1552-1560 ISSN：2391-5447
通讯作者：
Ren, Weihe
作者机构：
[Ren, Weihe] Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Hunan, Peoples R China.;[Li, Quan; Ren, Weihe; Qin, Feng] Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Key Lab Land Surface Pattern & Simulat, Beijing 100101, Peoples R China.;[Yi, Guitian] Hengyang Normal Univ, Hengyang 421002, Hunan, Peoples R China.
通讯机构：
[Ren, Weihe] H;[Ren, Weihe] C;Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Hunan, Peoples R China.;Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Key Lab Land Surface Pattern & Simulat, Beijing 100101, Peoples R China.
关键词：
Asian summer monsoon;2 kyr shift;interglaciations;atmospheric CO2 concentration
摘要：
Holocene records for the Asian Summer Monsoon (ASM) indicate that, apart for the last 2,000 years (“2 kyr shift”), solar insolation was the dominant factor controlling the monsoon climate. The aim of this review is to provide a synopsis of climate characteristics over the last 2 kyr, clarifying mechanisms for the diverse trend with Northern Hemisphere Summer Insolation (NHSI) records. Here, we initially review proxy-based climate reconstructions for the last 2 kyr, and then compare them with records from the last five interglacial periods. Finally, we examine potential physical mechanisms responsible for the “2 kyr shift.” Findings from this review indicate that the “2 kyr shift” is a representative pattern of Holocene climate change within the core area of the ASM, and the “2 kyr shift” could be mainly controlled by changes in atmospheric CO2 concentration. In addition, suggestions to address a more humid condition dominating the Asian monsoonal margin zones are offered.
通讯机构：
[Shunqing Zhong] C;College of Geography and Tourism, Hengyang Normal University, 421002 Hengyang, China<&wdkj&>Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
摘要：
A geographically constrained chronosequence of peatlands divided into three age classes (young, intermediate and old) was used to explore the role of biogeochemical influences, including electron donors and acceptors as well as chemical speciation of inorganic mercury (Hg(II)), on net formation of methylmercury (MeHg) as approximated by the fraction of MeHg to total mercury (THg) in the peat soil. We hypothesized that removing vascular plants would reduce availability of electron donors and thus net MeHg formation. However, we found no effect of the vascular plant removal. The sum of the potential electron donors (acetate, lactate, propionate and oxalate), the electron donation proxy organic C/Organic N, and the potential electron acceptors (Fe(III), Mn and sulfate) in porewater all showed significant correlations with the net MeHg formation proxies in peat soil (MeHg concentration and %MeHg of THg). Thus differences in both electron donor and acceptor availability may be contributing to the pattern of net MeHg formation along the chronosequence. In contrast, Hg(II) concentrations in peat porewater showed small differences along the gradient. A chemical speciation model successfully predicted the solubility of Hg and MeHg in the porewater. The modeling pointed to an enhanced concentration of Hg-polysulfide species in the younger peatlands as a potential factor behind increased Hg(II) solubility and methylation in the more nutrient-rich peatlands. This work contributes to the understanding of Hg and MeHg cycling in peatlands which can help guide mitigation measures to reduce aquatic MeHg biomagnification in peatland dominated landscapes. (C) 2021 The Authors. Published by Elsevier Ltd.
