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The study of short-term dynamics of soil moisture in the dry-hot valley area during rainfall process will help identify soil hydrological function. In this study, we analyzed the short-term responses of soil moisture to rainfall in Huajiang dry-hot valley of Guizhou, using研究干热河谷地区土壤水分在降雨过程中的短时动态变化,有助于揭示该地区的土壤水文功能。本研究选取贵州花江干热河谷作为研究区,运用原位监测法,获取不同坡位的高频土壤水分监测数据,分析土壤水分对降雨的短时动态响应特征。结果表明: 在整个监测期间,无论是坡上还是坡中,研究区各层土壤水分均为中等变异水平(15.2%≤变异系数CV≤29.7%),坡上土壤水分的波动幅度(CV=21.1%)大于坡中(CV=19.1%),0～5 cm土层(CV=26.2%)大于20～40 cm土层(CV=16.5%)。与坡中相比,坡上土壤水分对降雨的响应速度更快,降雨对土壤水分的补给量大、补给速率快;坡上的土壤水分补给速率与消退速率之差(2.3%·h

Groundwater is the most important water resource in arid regions. However, the groundwater traditional models and field measurements are limited due to the fluctuations in hydrological cycles and the difficulty in the accurate quantification of associated parameters. Here, we hypothesized that maximum potential tree height could be used to predict groundwater depth due to the hydraulic limitation of water transportation. To address this hypothesis, we measured two proxy indicators of maximum potential tree height, i.e., the maxima of heights and volumes, of three common dominant tree species in northwest China to construct classical measurement error (CME) model for predicting groundwater depth in an arid region. Our results showed that the optimal model based on maximum tree height had the best predictive performance of groundwater depth, particularly the tallest plant species. The CME model showed that maximum tree height played a vital role in predicting groundwater depth. Mathematically the model can be expressed as: [ E l n ( D w ) ln T h , θ ) = 7.11 - 1.85 E x ln T h , θ ) , where Dw and Th are respectively the theoretical values of groundwater depth and maximum tree height; x is the measured maximum tree height; θ = {7.11, −1.85, 7.19, 0.15, 1.91, 13.45}; R2 = 0.82; Marginal log-Likelihood = −131.04; RMSE = 0.33]. In addition, Leave-One-Out Cross-Validation together with correlation analysis indicated that groundwater depth prediction based on maximum tree height in arid regions was an accurate and promising approach. In conclusion, our study showed that the hydraulic limitation of water transportation led to a negative relationship between maximum tree height and groundwater depth. Our developed model for predicting groundwater depth with maximum tree height has provided the important basis for the conservation and management of groundwater resources in arid regions.

The hydrology of rivers recharged with reclaimed water is an important factor controlling its aquatic environment and biochemical processes, which change during the wet season. To understand the impacts of precipitation on hydrological conditions, water samples were collected from seven sites in three periods (before the wet season and during and after the maximum precipitation in July 2017, with 3.3 return periods) throughout a reclaimed water intake area of the Chaobai River in the Shunyi District, Beijing. The hydrogen-oxygen isotope characteristics and chloride content were measured. The results show that the hydrogen and oxygen isotopes of precipitation are mainly affected by the amount of the effect. The minor variation in the later period is due to changes in the sources of moisture. Within three days after precipitation, the slope runoff continues and the fraction of each section varies greatly. The reclaimed water reaches the downstream section through the preferred pathway. The water component ratio of the slope runoff increases from 2% to 85.6% in the direction of the flow, while the reclaimed water ratio decreases from 90% to 67%. The stream remains effluent from sections SY01 to SY05 that are recharged by the slope runoff, reclaimed water, and in-site river water, while the sections SY06 to SY07 are mainly recharged by the slope runoff and in-site river water within three days after the precipitation (the stream effluent is unremarkable).

Net primary productivity (NPP) and evapotranspiration (ET) are two key variables in the carbon and water cycles of terrestrial ecosystems. In this study, to test a newly developed NPP algorithm designed for HJ-1 A/B data and to evaluate the usage of HJ-1 A/B data in the quantitative assessment of environments, NPP and ET in Jinggangshan city, Jiangxi province, are calculated using HJ-1 A/B data. The results illustrate the following: (1) The NPP and ET in Jinggangshan city in 2010 both show obvious seasonal variation, with the highest values in summer and the lowest values in winter, and relatively higher values were observed in autumn than in spring. (2) The spatial pattern indicates that the annual NPP is high in the southern area in Jinggangshan city and low in the northern area. Additionally, high NPP is distributed in forests located in areas with high elevation, and low NPP is found in croplands at low elevations. ET has no significant north-south difference, with high values in the southeast and northwest and low values in the southwest, and high ET is distributed in forests at low elevations in contrast to low ET in forests in high-elevation areas and in cropland and shrub grassland in low-elevation areas. (3) Compared to the MODIS product, the range of HJ-1 NPP is larger, and the spatial pattern is more coincident with the topography. The range of HJ-1 ET is smaller than that of the MODIS product, and ET is underestimated to some extent but can reflect the effect of topography. This study suggests that the algorithm can be used to estimate NPP and ET in a subtropical monsoon climate if remotely sensed images with high spatial resolution are available.

A water quality model large-scale Non-Point Source pollution model was widely applied to deal with nonpoint source pollution in China. In this paper, the model was improved by adjusting the time step. The time scale of the solution module was modified to one day and half a month for the adhesion module. The Non-Point Source pollution loads in Haikou in 2008 were calculated by using the new model. The results show that the major pollutants of Haikou were the COD from large and small livestock, and the soluble pollution loads were much larger than the adsorbed pollution loads. Pollution loads of all types showed evident temporal and spatial trends. Moreover, the NPS pollution loads were dramatically larger in the flood season than in dry season. The distribution of average load of Non-Point Source pollution in Haikou originated from different areas showed significant spatial differences.

Rateless code usually generates a potentially infinite number of coded packets at the encoder and collects enough packets at the decoder to ensure reliable recovery of multiple information packets. The conventional rateless decoder usually works in a parallel manner which needs to initiate a new belief propagation (BP) decoding procedure upon each newly received collection of coded packets, thereby resulting in prohibitive decoding complexity in practice. In this paper, we present a novel serial decoding algorithm, i.e., the serial storage belief propagation (SS BP) algorithm, for rateless codes over noisy channels. Specifically, upon receiving a new group of coded packets, the decoder initiates a new attempt to decode all the packets received so far, using the results of the previous attempt as initial input. Moreover, in each iteration of the new attempt, the decoder serially propagates the messages group by group from the most recent one to the earliest one. In this way, the newly updated messages can be propagated faster, expediting the recovery of information packets. In addition, the proposed serial decoding algorithm has significantly lower complexity than the existing parallel decoding algorithms. Simulation results validate its effectiveness in AWGN, Rayleigh, and Rician fading channels.

An eco-hydrological model system (RIP_ N) was constructed to simulate the nitrogen (N) removal by riparian zone in reservoir catchment scale. As a case study, the N removal in Guanting Reservoir riparian zone from March to September in 2007 was estimated. At same time, the field simulated experiment was carried out in Yanqing experimental station, which lies in the northeast part of the catchment. With the experimental data and previous studies, the RIP_ N model was calibrated. RIP_ N model was consisted with two parts, which were soil chemical process modeling and plant growth modeling. Soil chemical processes considered the soil denitrification, nitrification and ammonium volatilization. Plant growth included net primary productivity (NPP) module, plant production allocation module and nutrition uptake module. The research indicated that the correlation coefficient between simulated value and monitored value was larger than 0.5, which proved the effectiveness and reliability of RIP_ N model in catchment scale simulating. The simulated results showed that the N removal loss by riparian zone in Guanting Reservoir catchment from March to September was 5.91 x 10(3) t. The model also identified the N removal functions of different land use. At present land use condition, the bottomland, forest land and grassland contributed positively environmental benefits and removed most of N. In the temporal scale, the N removal from March to September consisted 76.5% of annual removal load. On the contrary, the wetlands just removed 5.9% of N of whole watershed. By comparison, the riparian zone was recognized as critical location for non point source pollution prevention.

Employing remote sensing method to interpret the building volumetric ratio and aerosol status in Guangzhou, China. The relation between them and identified characteristics of their spatial distribution was analyzed. Results showed that building density and aerosol status are strongly correlated. It is indicated that the resistance of building to aerosol diffusing is one of factors influencing air pollution in urban area. On the basis of calculated results, building voluminous ratio of 5.6 is taken as the threshold impacting on aerosol diffusing, so the building voluminous ratio of Guangzhou should be limited to less than 5.6 in order to alleviate air pollution.