Measurements of evapotranspiration from eddy-covariance systems and large aperture scintillometers in the Hai River Basin, China

Evaluation of SVM, ELM and four tree-based ensemble models for predicting daily reference evapotranspiration using limited meteorological data in different climates of China

[1] Agreement among instruments is very important for the Multi-Scale Observation Experiment on Evapotranspiration over heterogeneous land surfaces of The Heihe Watershed Allied Telemetry Experimental Research (HiWATER-MUSOEXE), particularly in regard to radiation and turbulent flux measurements Before HiWATER-MUSOEXE was conducted, 20 eddy covariance (EC) system sets, 18 radiometer sets, and seven large aperture scintillometers (LASs) sets were intercompared over the Gobi desert between 14 and 24 May 2012 For radiometers, the four-component radiation measurements exhibited good agreement—the average root-mean-square error (RMSE) and mean relative error (MRE) for the net radiation were 1038 W m−2 and 124%, respectively With regard to the EC systems, the best consistency for sensible heat fluxes was found among CSAT3 sonic anemometers and Li7500A/Li7500/EC150 combinations (average RMSE, 1230 W m−2 and MRE, −136%), followed by Gill sonic anemometers and Li7500A/Li7500 combinations when a proper angle of attack correction method was applied (average RMSE, 1675 W m−2 and MRE, −552%) The sensible heat flux measured using different LASs agreed well with high correlation coefficients—the average RMSE and MRE values were 1026 W m−2 and 548% for boundary layer scintillometer (BLS) 900, 1632 W m−2 and 1047% for BLS450, and 1438 W m−2 and −372% for ZZLAS, respectively The EC and LAS measurements were compared and agreed well over homogeneous underlying surfaces, which also indicated that the EC and LAS measurements would be comparable in the follow-up experiment The intercomparison results can be used to determine instrument placement and are very helpful for subsequent data analysis

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2013JD020260

Intercomparison of surface energy flux measurement systems used during the HiWATER-MUSOEXE

Research on land surface processes at the catchment scale has drawn much attention over the past few decades, and a number of watershed observatories have been established worldwide. The Heihe River Basin (HRB), which contains the second largest inland river in China, is an ideal natural field experimental area for investigation of land surface processes involving diverse landscapes and the coexistence of cold and arid regions. The Heihe Integrated Observatory Network was established in 2007. For long-term observations, a hydrometeorological observatory, ecohydrological wireless sensor network, and satellite remote sensing are now in operation. In 2012, a multiscale observation experiment on evapotranspiration over heterogeneous land surfaces was conducted in the midstream region of the HRB, which included a flux observation matrix, wireless sensor network, airborne remote sensing, and synchronized ground measurements. Under an open data policy, the datasets have been publicly released following careful data processing and quality control. The outcomes highlight the integrated research on land surface processes in the HRB and include observed trends, scaling methods, high spatiotemporal resolution remote sensing products, and model–data integration in the HRB, all of which are helpful to other endorheic basins in the “Silk Road Economic Belt.” Henceforth, the goal of the Heihe Integrated Observatory Network is to develop an intelligent monitoring system that incorporates ground-based observatory networks, unmanned aerial vehicles, and multi-source satellites through the Internet of Things technology. Furthermore, biogeochemical processes observation will be improved, and the study of integrating ground observations, remote sensing, and large-scale models will be promoted further.

The Heihe Integrated Observatory Network: A Basin-Scale Land Surface Processes Observatory in China

Evaluation of random forests and generalized regression neural networks for daily reference evapotranspiration modelling.

. We analyzed the seasonal variations of energy balance components over three different surfaces: irrigated cropland (Yingke, YK), alpine meadow (A'rou, AR), and spruce forest (Guantan, GT). The energy balance components were measured using eddy covariance (EC) systems and a large aperture scintillometer (LAS) in the Heihe River Basin, China, in 2008 and 2009. We also determined the source areas of the EC and LAS measurements with a footprint model for each site and discussed the differences between the sensible heat fluxes measured with EC and LAS at AR. The results show that the main EC source areas were within a radius of 250 m at all of the sites. The main source area for the LAS (with a path length of 2390 m) stretched along a path line approximately 2000 m long and 700 m wide. The surface characteristics in the source areas changed with the season at each site, and there were characteristic seasonal variations in the energy balance components at all of the sites. The sensible heat flux was the main term of the energy budget during the dormant season. During the growing season, however, the latent heat flux dominated the energy budget, and an obvious "oasis effect" was observed at YK. The sensible heat fluxes measured by LAS at AR were larger than those measured by EC at the same site. This difference seems to be caused by the so-called energy imbalance phenomenon, the heterogeneity of the underlying surfaces, and the difference between the source areas of the LAS and EC measurements.

/pdf/a-comparison-of-eddy-covariance-and-large-aperture-3q1dngnlgw.pdf

A comparison of eddy-covariance and large aperture scintillometer measurements with respect to the energy balance closure problem

Objective: To evaluate the effects on short-term clinical outcomes and long-term quality of life of laparoscopic-assisted radical proximal gastrectomy with esophageal gastric tube anastomosis versus total gastrectomy with Roux-en-Y anastomosis for adenocarcinoma of the esophagogastric junction. Methods: This was a propensity score matching, retrospective, cohort study. Clinicopathological data of 184 patients with adenocarcinoma of the esophagogastric junction admitted to two medical centers in China from January 2016 to January 2021 were collected (147 in the First Affiliated Hospital of Xiamen University and 37 in the Affiliated Hospital of Qinghai University). All patients had undergone laparoscopic-assisted radical gastrectomy. They were divided into two groups based on the extent of tumor resection and technique used for digestive tract reconstruction. A proximal gastrectomy with reconstruction by esophageal gastric tube anastomosis group comprised 82 patients and a total gastrectomy with reconstruction by Roux-en-Y anastomosis group comprised 102 patients. These groups differed significantly in the following baseline characteristics: age, preoperative hemoglobin, preoperative albumin, tumor length, tumor differentiation, and tumor TNM stage (all P<0.05). To eliminate potential bias caused by unequal distribution between the two groups, 1∶1 matching was performed by the nearest neighbor matching method. The 13 matched variables comprised sex, age, height, body mass, body mass index, preoperative glucose, preoperative hemoglobin, preoperative total protein, preoperative albumin, neoadjuvant radiotherapy, tumor length, degree of differentiation, and pathological TNM stage. Postoperative complications, postoperative nutritional status, incidence of reflux esophagitis 1 year after surgery, and quality of life were compared between the two groups. Results: After propensity score matching, 60 patients each were enrolled in the proximal gastrectomy with esophageal gastric tube anastomosis and total gastrectomy with Roux-en-Y anastomosis groups. The baseline characteristics were comparable between these groups (all P>0.05). There were no significant differences between the two groups in operative time, intraoperative bleeding, time to semifluid diet, postoperative hospital days, tumor length, and total hospital costs (P>0.05). Patients in the proximal gastrectomy with esophageal gastric tube anastomosis group had earlier postoperative gastric tube and abdominal drainage tube removal time than those in the total gastrectomy with Roux-en-Y anastomosis group (t=-2.183, P=0.023 and t=-4.073, P<0.001, respectively). In contrast, significantly fewer lymph nodes were cleared and significantly fewer lymph nodes were positive in the proximal gastrectomy with esophageal gastric tube anastomosis group than in the total gastrectomy with Roux-en-Y anastomosis group (t=-5.754, P<0.001 and t=-2.575, P=0.031, respectively). The incidence of early postoperative complications was 43.3% (26/60) in the total gastrectomy with Roux-en-Y anastomosis group; this is not significantly higher than the 26.7% (16/60) in the proximal gastrectomy with esophageal gastric tube anastomosis group (χ2=3.663，P=0.056). The incidences of pulmonary infection (31.7%, 19/60) and pleural effusion (30.0%, 18/60) were significantly higher in the total gastrectomy with Roux-en-Y anastomosis group than in the proximal gastrectomy with esophageal gastric tube anastomosis group (13.3%, 8/60 and 8.3%, 5/60, respectively); these differences are significant (χ2=8.711, P=0.003 and χ2=11.368, P=0.001, respectively). All early complications were successfully treated before discharge. The incidence of long-term postoperative complications was 20.0% (12/60) in the total gastrectomy with Roux-en-Y anastomosis group and 35.0% (21/60) in the proximal gastrectomy with esophageal gastric tube anastomosis group; this difference is not significant (χ2=3.386，P=0.066). The incidence of reflux esophagitis was 23.3% (14/60) in the proximal gastrectomy with esophageal gastric tube anastomosis group; this is significantly higher than the 1.7% (1/60) in the total gastrectomy with Roux-en-Y anastomosis group (χ2=12.876, P<0.001). Body mass index had decreased significantly in both groups 1 year after surgery compared with preoperatively; however, the difference between the two groups was not significant (P>0.05). The differences in hemoglobin and albumin concentrations between 1 year postoperatively and preoperatively were not significant (both P>0.05). Quality of life was assessed using the Visick grade. Visick grade I dominated in both groups. The percentage of patients with Visick II and III in the total gastrectomy with Roux-en-Y anastomosis group was 11.7% (7/60), which is significantly lower than the 33.3% (20/60) in the proximal gastrectomy with esophageal gastric tube anastomosis group (χ2=8.076, P=0.004). No patients in either group had a grade IV quality of life. Conclusions: Both proximal gastrectomy with esophageal gastric tube anastomosis and total gastrectomy with Roux-en-Y anastomosis laparoscopic-assisted radical surgery for adenocarcinoma of the esophagogastric junction are safe and feasible. However, both procedures have their own advantages and disadvantages in terms of postoperative complications. The incidence of reflux esophagitis is higher after proximal gastrectomy with esophageal gastric tube anastomosis, whereas the long-term quality of life is lower than that of patients after total gastrectomy with Roux-en-Y anastomosis.

[Short-term outcomes and long-term quality of life after undergoing radical proximal gastrectomy with esophageal gastric tube anastomosis and total gastrectomy with Roux-en-Y anastomosis for Siewert type II and III adenocarcinoma of the esophagogastric junction: A propensity score matching analysis]

Z. W. Xu

Papers

A comparison of eddy-covariance and large aperture scintillometer measurements with respect to the energy balance closure problem

Measurements of evapotranspiration from eddy-covariance systems and large aperture scintillometers in the Hai River Basin, China

[Short-term outcomes and long-term quality of life after undergoing radical proximal gastrectomy with esophageal gastric tube anastomosis and total gastrectomy with Roux-en-Y anastomosis for Siewert type II and III adenocarcinoma of the esophagogastric junction: A propensity score matching analysis]