An evaluation of sea surface height assimilation using along-track and gridded products based on the Regional Ocean Modeling System(ROMS) and the four-dimensional variational data assimilation

Remote sensing products are significant in the data assimilation of an ocean model. Considering the resolution and space coverage of different remote sensing data, two types of sea surface height（SSH） product are employed in the assimilation, including the gridded products from AVISO and the original along-track observations used in the generation. To explore their impact on the assimilation results, an experiment focus on the South China Sea（SCS） is conducted based on the Regional Ocean Modeling System（ROMS） and the four-dimensional variational data assimilation（4 DVAR） technology. The comparison with EN4 data set and Argo profile indicates that, the along-track SSH assimilation result presents to be more accurate than the gridded SSH assimilation, because some noises may have been introduced in the merging process. Moreover, the mesoscale eddy detection capability of the assimilation results is analyzed by a vector geometry–based algorithm. It is verified that, the assimilation of the gridded SSH shows superiority in describing the eddy＇s characteristics, since the complete structure of the ocean surface has been reconstructed by the original data merging.

Study on the treatment and the utilization of the Baosteel casting residue and the new grid engineering technology

This study summarizes some serious disharmonious problems that ubiquitously exist in the casting residue recycling of steel plants, such as large land occupation, low operational efficiency, hidden hazards, huge resource and energy consumption, serious environmental pollution and so on. It analyzes the necessity of the on-line innovation and recycling based on the present situation of Baosteel. It states the innovation of the new grid technology and the achievements of its integrated application at Baosteel. It also summarizes and elaborates some green technology features of the treatment and the utilization of the Baosteel casting residue and the new grid technology, such as safety,energy-saving and environmental protection. In addition,it lays out the prospects for the development and application of the technology.

Hybrid global gridded snow products and conceptual simulations of distributed snow budget:evaluation of different scenarios in a mountainous watershed

Considering snowmelt in mountainous areas as the important source of streamflow,the snow accumulation/melting processes are vital for accurate simulation of the hydrological regimes.The lack of snow-related data and its uncertainties/conceptual ambiguity in snowpack modeling are the different challenges of developing hydroclimatological models.To tackle these challenges,Global Gridded Snow Products(GGSPs)are introduced,which effectively simplify the identification of the spatial characteristics of snow hydrological variables.This research aims to investigate the performance of multisource GGSPs using multi-stage calibration strategies in hydrological modeling.The used GGSPs were Snow-Covered Area(SCA)and Snow Water Equivalent(SWE),implemented individually or jointly to calibrate an appropriate water balance model.The study area was a mountainous watershed located in Western Iran with a considerable contribution of snowmelt to the generated streamflow.The results showed that using GGSPs as complementary information in the calibration process,besides streamflow time series,could improve the modeling accuracy compared to the conventional calibration,which is only based on streamflow data.The SCA with NSE,KGE,and RMSE values varying within the ranges of 0.47–0.57,0.54–0.65,and 4–6.88,respectively,outperformed the SWE with the corresponding metrics of 0.36–0.59,0.47–0.60,and 5.22–7.46,respectively,in simulating the total streamflow of the watershed.In addition to the superiority of the SCA over SWE,the twostage calibration strategy reduced the number of optimized parameters in each stage and the dependency of internal processes on the streamflow and improved the accuracy of the results compared with the conventional calibration strategy.On the other hand,the consistent contribution of snowmelt to the total generated streamflow(ranging from 0.9 to 1.47)and the ratio of snow melting to snowfall(ranging from 0.925 to 1.041)in different calibration strategies and models resulted in a reliable simulation of the model.

Assessing remotely sensed and reanalysis products in characterizing surface soil moisture in the Mongolian Plateau

Soil moisture(SM)plays a crucial role in the dynamics of coupled atmosphere,water,energy,and carbon cycles.In this study,the spatiotemporal distribution and variations of SM in the Mongolian Plateau were investigated for the period of 1982-2018 based on four gridded SM datasets.Taking the observed SM from 33 monitoring stations as a reference,the reliability of these four gridded products was validated,and the three-cornered hat(TCH)method was also applied to evaluate their uncertainties.Major results indicated that all these four products underestimated the SM in this region at different levels.The ERA-Interim SM performed much better than other three products,with a higher R of 0.53 and lower ubRMSE of 0.0378 m^(3)·m^(−3).Except for ECV,the surface SM exhibited a decreasing trend at−0.0004 to−0.0008 m^(3)·m^(−3)/decade in the warm season(from April to October)over the past 37 years.The greatest decreases in SM occurred in the summer season.Precipitation change plays a more important role in explaining the variations of SM than temperature reported by partial correlation analysis.The results of this study will benefit our understanding of the climate change effects and the protection of the ecological systems in this region.