Xujun Han
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View article: Estimation of Tree Canopy Closure Based on U-Net Image Segmentation and Machine Learning Algorithms
Estimation of Tree Canopy Closure Based on U-Net Image Segmentation and Machine Learning Algorithms Open
Canopy closure is a critical indicator reflecting forest structure, biodiversity, and ecological balance. This study proposes an estimation method integrating U-Net segmentation with machine learning, significantly improving accuracy throu…
View article: An operational Airborne-Ground Integrate observation scheme for validating land surface temperature over heterogeneous surface
An operational Airborne-Ground Integrate observation scheme for validating land surface temperature over heterogeneous surface Open
At present, there are more than 30 satellite remote sensing Land Surface Temperature (LST) products from kilometers to hectometers resolutions. The accuracy of these products is the key issue for further application. The validation of LST …
View article: Identification and Mapping of Eucalyptus Plantations in Remote Sensing Data Using CCDC Algorithm and Random Forest
Identification and Mapping of Eucalyptus Plantations in Remote Sensing Data Using CCDC Algorithm and Random Forest Open
Eucalyptus plantations are one of the primary artificial forests in southern China, experiencing rapid expansion in recent years due to their significant socio-economic benefits. This expansion has raised concerns about the ecological envi…
View article: The Respective Effects of Vapor Pressure Deficit and Soil Moisture on Ecosystem Productivity in Southwest China
The Respective Effects of Vapor Pressure Deficit and Soil Moisture on Ecosystem Productivity in Southwest China Open
This study aims to examine the individual and combined effects of soil moisture (SM) and vapor pressure deficit (VPD) on ecosystem productivity in Southwest China. Utilizing the community land model (CLM) to simulate the regional soil mois…
View article: Comparison and Validation of Multiple Medium- and High-Resolution Land Cover Products in Southwest China
Comparison and Validation of Multiple Medium- and High-Resolution Land Cover Products in Southwest China Open
The rapid advancement of remote sensing technology has given rise to numerous global- and regional-scale medium- to high-resolution land cover (LC) datasets, making significant contributions to the exploration of worldwide environmental sh…
View article: Improved evapotranspiration modeling by incorporating seasonal irrigation into a land surface model
Improved evapotranspiration modeling by incorporating seasonal irrigation into a land surface model Open
Irrigation is very important for maintaining the agricultural production and sustaining the increasing population of India. The irrigation requirement can be estimated with land surface models. The irrigation modeling tends to be affected …
View article: Land Data Assimilation: Harmonizing Theory and Data in Land Surface Process Studies
Land Data Assimilation: Harmonizing Theory and Data in Land Surface Process Studies Open
Data assimilation plays a dual role in advancing the “scientific” understanding and serving as an “engineering tool” for the Earth system sciences. Land data assimilation (LDA) has evolved into a distinct discipline within geophysics, faci…
View article: Global Per Capita CO2 Emission Trends
Global Per Capita CO2 Emission Trends Open
In recent years, carbon emissions have become a hot spot issue, and countries have made efforts to control the increasing rate of CO2 concentration. Prior studies have mainly focused on the national total carbon emissions, but per capita c…
View article: Spatial–Temporal Dynamics of Forest Extent Change in Southwest China in the Recent 20 Years
Spatial–Temporal Dynamics of Forest Extent Change in Southwest China in the Recent 20 Years Open
Deforestation is thought of as a huge threat to carbon neutrality and the development of contemporary society and it has brought wide interest and attention in the science community to develop new methods to identify and quantify the occur…
View article: Spatial and Temporal Characteristics of Drought Events in Southwest China over the Past 120 Years
Spatial and Temporal Characteristics of Drought Events in Southwest China over the Past 120 Years Open
Global climate change, especially extreme drought events, presents a complicated challenge to humanity and Earth’s system in the 21st century. As an extremely important carbon sink region in China, Southwest China has encountered frequent …
View article: Attribution of Extreme Drought Events and Associated Physical Drivers across Southwest China Using the Budyko Framework
Attribution of Extreme Drought Events and Associated Physical Drivers across Southwest China Using the Budyko Framework Open
Drought is a meteorological phenomenon that negatively impacts agricultural production. In recent years, southwest China has frequently experienced agricultural droughts; these have significantly impacted the economy and the ecological env…
View article: Uncertainty Quantification of Satellite Soil Moisture Retrieved Precipitation in the Central Tibetan Plateau
Uncertainty Quantification of Satellite Soil Moisture Retrieved Precipitation in the Central Tibetan Plateau Open
SM2RAIN is a well-established methodology for estimating precipitation from satellite or observed soil moisture and it has been applied as a complementary approach to conventional precipitation monitoring methods. However, satellite soil m…
View article: The respective effects of atmospheric vapor pressure and soil moisture on ecosystem productivity in Southwest China
The respective effects of atmospheric vapor pressure and soil moisture on ecosystem productivity in Southwest China Open
Drought is considered as a key factor restricting the growth of plants. It is critical to investigate the impact of drought stress on vegetation and understand the respective effects of Soil Moisture (SM) and Vapor Pressure Difference (VPD…
View article: Retrieving Soil Physical Properties by Assimilating SMAP Brightness Temperature Observations into the Community Land Model
Retrieving Soil Physical Properties by Assimilating SMAP Brightness Temperature Observations into the Community Land Model Open
This paper coupled a unified passive and active microwave observation operator—namely, an enhanced, physically-based, discrete emission-scattering model—with the community land model (CLM) in a data assimilation (DA) system. By implementin…
View article: Monitoring of Extreme Agricultural Drought of the Past 20 Years in Southwest China Using GLDAS Soil Moisture
Monitoring of Extreme Agricultural Drought of the Past 20 Years in Southwest China Using GLDAS Soil Moisture Open
Drought can cause severe agricultural economic losses and hinder social and economic development. To manage drought, the process of drought events needs to be described with the help of an effective drought indicator. As a comprehensive va…
View article: Multi-Source Hydrological Data Products to Monitor High Asian River Basins and Regional Water Security
Multi-Source Hydrological Data Products to Monitor High Asian River Basins and Regional Water Security Open
This project explored the integrated use of satellite, ground observations and hydrological distributed models to support water resources assessment and monitoring in High Mountain Asia (HMA). Hydrological data products were generated taki…
View article: Retrieving Soil Physical Properties via Assimilating SMAP Brightness Temperature Observations in the Community Land Model
Retrieving Soil Physical Properties via Assimilating SMAP Brightness Temperature Observations in the Community Land Model Open
<p>Basic soil physical properties (i.e., soil texture and organic matter) and associated soil hydraulic properties (i.e., soil water retention curve and hydraulic conductivity) play an essential role in land surface models (LSMs) for…
View article: Retrieval of basic soil physical properties by assimilating radiometry observations in the community land surface model
Retrieval of basic soil physical properties by assimilating radiometry observations in the community land surface model Open
<p>Accurate basic soil properties information is fundamental for obtaining reliable soil moisture using land surface models. In view of the passive microwave remote sensing, basic soil properties have an impact on soil dielectric con…
View article: Assessment of the uncertainty related to irrigation modeling by a land surface model across India
Assessment of the uncertainty related to irrigation modeling by a land surface model across India Open
<p>Irrigation is very important for maintaining the agricultural production and sustaining the increasing population of India. The irrigation requirement can be estimated with land surface models by modeling water storage changes but…
View article: Responses of Seasonal Indicators to Extreme Droughts in Southwest China
Responses of Seasonal Indicators to Extreme Droughts in Southwest China Open
Significant impact of extreme droughts on human society and ecosystem has occurred in many places of the world, for example, Southwest China (SWC). Considerable research concentrated on analyzing causes and effects of droughts in SWC, but …
View article: Using Solar-Induced Chlorophyll Fluorescence Observed by OCO-2 to Predict Autumn Crop Production in China
Using Solar-Induced Chlorophyll Fluorescence Observed by OCO-2 to Predict Autumn Crop Production in China Open
The remote sensing of solar-induced chlorophyll fluorescence (SIF) has attracted considerable attention as a new monitor of vegetation photosynthesis. Previous studies have revealed the close correlation between SIF and terrestrial gross p…
View article: Land Use Change and Climate Variation in the Three Gorges Reservoir Catchment from 2000 to 2015 Based on the Google Earth Engine
Land Use Change and Climate Variation in the Three Gorges Reservoir Catchment from 2000 to 2015 Based on the Google Earth Engine Open
Possible environmental change and ecosystem degradation have received increasing attention since the construction of Three Gorges Reservoir Catchment (TGRC) in China. The advanced Google Earth Engine (GEE) cloud-based platform and the larg…
View article: Research progress and prospect of observation and simulation of carbon cycle in the karst areas of Southwest China
Research progress and prospect of observation and simulation of carbon cycle in the karst areas of Southwest China Open
摘要:
View article: Can Drip Irrigation be Scheduled with Cosmic‐Ray Neutron Sensing?
Can Drip Irrigation be Scheduled with Cosmic‐Ray Neutron Sensing? Open
Core Ideas Cosmic‐ray neutron sensing (CRNS) was used in a drip‐irrigated field. Soil water content was estimated from CRNS. Neutron transport was simulated for the drip‐irrigated field. CRNS has limitations for irrigation scheduling of dr…
View article: Global Land Surface Temperature Influenced by Vegetation Cover and PM2.5 from 2001 to 2016
Global Land Surface Temperature Influenced by Vegetation Cover and PM2.5 from 2001 to 2016 Open
Land surface temperature (LST) is an important parameter to evaluate environmental changes. In this paper, time series analysis was conducted to estimate the interannual variations in global LST from 2001 to 2016 based on moderate resoluti…
View article: Evaluation and uncertainty analysis of regional-scale CLM4.5 net carbon flux estimates
Evaluation and uncertainty analysis of regional-scale CLM4.5 net carbon flux estimates Open
Modeling net ecosystem exchange (NEE) at the regional scale with land surface models (LSMs) is relevant for the estimation of regional carbon balances, but studies on it are very limited. Furthermore, it is essential to better understand a…
View article: SMOS brightness temperature assimilation into the Community Land Model
SMOS brightness temperature assimilation into the Community Land Model Open
SMOS (Soil Moisture and Ocean Salinity mission) brightness temperatures at a single incident angle are assimilated into the Community Land Model (CLM) across Australia to improve soil moisture simulations. Therefore, the data assimilation …
View article: State and parameter estimation of two land surface models using the ensemble Kalman filter and the particle filter
State and parameter estimation of two land surface models using the ensemble Kalman filter and the particle filter Open
Land surface models (LSMs) use a large cohort of parameters and state variables to simulate the water and energy balance at the soil–atmosphere interface. Many of these model parameters cannot be measured directly in the field, and require…
View article: Evaluation of a cosmic-ray neutron sensor network for improved land surface model prediction
Evaluation of a cosmic-ray neutron sensor network for improved land surface model prediction Open
In situ soil moisture sensors provide highly accurate but very local soil moisture measurements, while remotely sensed soil moisture is strongly affected by vegetation and surface roughness. In contrast, cosmic-ray neutron sensors (CRNSs) …