Land-atmosphere fluxes and concentrations of CFC-11 and CFC-12 based on in situ observations from a coastal salt marsh in eastern China: Implications for CFC remediation

2021 ◽  
Vol 172 ◽  
pp. 112848
Author(s):  
Jinshu Wang ◽  
Yingjia Cao ◽  
Jinxin Wang
Keyword(s):  
Salt Marsh ◽  
Eastern China ◽  
Coastal Salt Marsh ◽  
In Situ Observations

Evaluation of multiple soil moisture products using in-situ observations over China

2021 ◽  
Author(s):  
Huiqing Li ◽  
Aizhong Ye ◽  
Yuhang Zhang ◽  
Wenwu Zhao
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Yellow River ◽  
Eastern China ◽  
Land Surface Model ◽  
Spatial And Temporal Variation ◽  
Surface Model ◽  
Drought Assessment ◽  
In Situ Observations

<p>Soil moisture (SM), a vital variable in the climate system, is applied in many fields. But the existing SM data sets from different sources have great uncertainty, hence need comprehensive verification. In this study, we collected and evaluated ten latest commonly used SM products over China, including four reanalysis data (ERA-Interim, ERA5, NCEP R2 and CFSR/CFSV2), three land surface model products (GLDAS 2.1 Noah, CLSM and VIC) and three remote sensing products (ESA CCI ACTIVE, COMBINED and PASSIVE). These products in their overlap period (2000-2018) were inter-compared in spatial and temporal variation. In addition, their accuracy was verified by a large quantity of in-situ observations. The results show that the ten SM products have roughly similar spatial patterns and small inter-annual differences, but there are still some deviations varying in regions and products. ERA5 displays the most encouraging overall performance in China. The estimates of SM in the northwest of China among all products generally perform poorly on capturing in-situ SM variability due to less coverage of observations. CLSM and ERA5 have a satisfactory correlation coefficient with the observed SM (R>0.7) in the northeast and south of China, respectively. ESA CCI ACTIVE performs with the optimal mean Equitable Threat Score (ETS) value, which indicates the promising ability to drought assessment, followed by CFSR/CFSV2 and ERA5. Specifically, ESA CCI ACTIVE expresses higher ETS in the Yellow River Basin, while CFSR/CFSV2 and ERA5 are more applicable in most areas of the eastern China. This study provides a reasonable reference for the application of SM products in China.</p>

The flux of methyl chloride along an elevational gradient of a coastal salt marsh, Eastern China

2006 ◽  
Vol 40 (34) ◽  
pp. 6592-6605 ◽  
Author(s):  
Jinxin Wang ◽  
Rongjin Li ◽  
Yingyan Guo ◽  
Pei Qin ◽  
Shucun Sun
Keyword(s):  
Salt Marsh ◽  
Eastern China ◽  
Methyl Chloride ◽  
Elevational Gradient ◽  
Coastal Salt Marsh

scholarly journals Multi-model evaluation of short-lived pollutant distributions over East Asia during summer 2008

2015 ◽  
Vol 15 (7) ◽  
pp. 11049-11109 ◽  
Author(s):  
B. Quennehen ◽  
J.-C. Raut ◽  
K. S. Law ◽  
G. Ancellet ◽  
C. Clerbaux ◽  
...  
Keyword(s):  
Eastern China ◽  
Regional Model ◽  
Vertical Profiles ◽  
Model Resolution ◽  
Northern India ◽  
Rural Environments ◽  
In Situ Observations ◽  
Aerosol Backscatter ◽  
Pollution Episodes

Abstract. The ability of six global and one regional model to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over Asia in summer 2008 is evaluated using satellite and in-situ observations. Whilst ozone precursors (NO2 and CO) are generally underestimated by the models in the troposphere, surface NO2 concentrations are overestimated, suggesting that emissions of NOx are too high. Ozone integrated columns and vertical profiles are generally well modeled, but the global models face difficulties simulating the ozone gradient at the surface between urban and rural environments, pointing to the need to increase model resolution. The accuracy of simulated aerosol patterns over eastern China and northern India varies between the models, and although most of the models reproduce the observed pollution features over eastern China, significant biases are noted in the magnitude of optical properties (aerosol optical depth, aerosol backscatter). These results have important implications for accurate prediction of pollution episodes affecting air quality and the radiative effects of these short-lived climate pollutants over Asia.

scholarly journals Evaluation of a multi-satellite soil moisture product and the Community Land Model 4.5 simulation in China

2015 ◽  
Vol 12 (5) ◽  
pp. 5151-5186 ◽  
Author(s):  
B. Jia ◽  
J. Liu ◽  
Z. Xie
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Surface Soil ◽  
Eastern China ◽  
Surface Model ◽  
Surface Soil Moisture ◽  
Community Land Model ◽  
Soil Moisture Data ◽  
In Situ Observations

Abstract. Twenty years of in situ soil moisture data from more than 300 stations located in China are used to perform an evaluation of two surface soil moisture datasets: a microwave-based multi-satellite product (ECV-SM) and the land surface model simulation from the Community Land Model 4.5 (CLM4.5). Both soil moisture products generally show a good agreement with in situ observations. The ECV-SM product has a low bias, with a root mean square difference (RMSD) of 0.075 m3 m-3, but shows a weak correlation with in situ observations (R = 0.41). In contrast, the CLM4.5 simulation, forced by an observation-based atmospheric forcing data, produces better temporal variation of surface soil moisture (R = 0.52), but shows a clear overestimation (bias = 0.05 m3 m-3) and larger RMSD (0.09 m3 m-3), especially in eastern China, caused by inaccurate descriptions of soil characteristics. The ECV-SM product is more likely to be superior in semi-arid regions, mainly because of the accurate retrievals and high observation density, but inferior over areas covered by dense vegetation. Furthermore, it shows a stable to slightly increasing performance in China, except for a decrease during the 2007–2010 blending period. Results from this study can provide comprehensive insight into the performances of the two soil moisture datasets in China, which will be useful for their improvements in merging algorithms or model simulations and for applications in soil moisture data assimilation.

scholarly journals Summertime photochemistry during CAREBeijing-2007: RO<sub> x</sub> budgets and O<sub>3</sub> formation

2012 ◽  
Vol 12 (2) ◽  
pp. 4679-4717 ◽  
Author(s):  
Z. Liu ◽  
Y. Wang ◽  
D. Gu ◽  
C. Zhao ◽  
L. G. Huey ◽  
...  
Keyword(s):  
Transport Model ◽  
Control Strategies ◽  
Eastern China ◽  
Heterogeneous Reactions ◽  
Transition Regime ◽  
Oxygenated Volatile Organic Compounds ◽  
In Situ Observations ◽  
Reactive Uptake Coefficient ◽  
Beijing China

Abstract. We analyze summertime photochemistry near the surface over Beijing, China, using a 1-D photochemical model (Regional chEmical and trAnsport Model, REAM-1D) constrained by in situ observations, focusing on the budgets of ROx (OH + HO2 + RO2) radicals and O3 formation. The daytime average of total ROx primary production rate in Beijing is ~6.6 ppbv h−1, among the highest found in urban atmospheres. The largest primary ROx source in Beijing is photolysis of oxygenated volatile organic compounds (OVOCs), which produces HO2 and RO2 at average daytime rates of 2.5 ppbv h−1 and 1.7 ppbv h−1, respectively. Photolysis of excess HONO from the unknown heterogeneous source is a predominant primary OH source at 2.2 ppbv h−1, much larger than that of O1D + H2O (0.4 ppbv h−1). The largest ROx sink is via OH + NO2 reaction (1.6 ppbv h−1), followed by formation of RO2NO2 (1.0 ppbv h−1) and RONO2 (0.7 ppbv h−1). Due to the large aerosol surface area, aerosol uptake of HO2 appears to be another important radical sink, although the estimate of its magnitude is highly variable depending on the reactive uptake coefficient value used. The daytime average O3 production and loss rates are 32 ppbv h−1 and 6.2 ppbv h−1, respectively. Assuming NO2 to be the source of excess HONO, the NO2 to HONO transformation leads to significant O3 loss and reduction of its lifetime. Our observation-based modeling analyses suggest that VOCs and heterogeneous reactions (e.g. HONO formation and aerosol uptake HO2) play major roles in the primary radical budget and O3 formation in Beijing. Among the VOC precursors for OVOCs, which strongly affect ROx budgets and O3 formation, aromatics are the largest contributor. One important ramification is that O3 production is neither NOx nor VOC limited, but in a transition regime, where reduction of either NOx or VOCs could result in reduction of O3 production. The transition regime implies more flexibility in the O3 control strategies than a binary system of either NOx or VOC limited regime. Further research on the spatial extent of the transition regime over the polluted eastern China is critically important for controlling regional O3 pollution.

Effects of in situ experimental air warming on the soil respiration in a coastal salt marsh reclaimed for agriculture

2013 ◽  
Vol 371 (1-2) ◽  
pp. 487-502 ◽  
Author(s):  
Qicheng Zhong ◽  
Qin Du ◽  
Jinnan Gong ◽  
Chao Zhang ◽  
Kaiyun Wang
Keyword(s):  
Salt Marsh ◽  
Soil Respiration ◽  
Coastal Salt Marsh
Sign in / Sign up

Export Citation Format

Share Document