Investigation of biogenic volatile organic compounds emissions in the Qinghai-Tibetan Plateau.

Biogenic volatile organic compounds (BVOCs), which are produced and emitted by plants, have significant chemical reactivity in the atmosphere and impacting climate change. Qinghai Province, a vital component of the plateau, has abundant vegetation resources, primarily grasslands and forests, yet BVOCs emissions and their impact on air quality remain understudied. In this study, the emissions rates and compositions of BVOCs from seven dominant vegetation types in Qinghai Province were sampled and analyzed using a closed-loop stripping dynamic headspace sampling approach combined with GC-MS, and the total emissions of BVOCs in Qinghai province in 2021 were estimated by using G95 model.

The Influences of Drought and Land-Cover Conversion on Inter-Annual Variation of NPP in the Three-North Shelterbelt Program Zone of China Based on MODIS Data.

Terrestrial ecosystems greatly contribute to carbon (C) emission reduction targets through photosynthetic C uptake.Net primary production (NPP) represents the amount of atmospheric C fixed by plants and accumulated as biomass. The Three-North Shelterbelt Program (TNSP) zone accounts for more than 40% of China's landmass.

The impact of winter heating on air pollution in China.

Fossil-fuel combustion related winter heating has become a major air quality and public health concern in northern China recently. We analyzed the impact of winter heating on aerosol loadings over China using the MODIS-Aqua Collection 6 aerosol product from 2004-2012. Absolute humidity (AH) and planetary boundary layer height (PBL) -adjusted aerosol optical depth (AOD*) was constructed to reflect ground-level PM2.

[Extraction and analysis of solar-induced chlorophyll fluorescence of wheat with ground-based hyperspectral imaging system].

Dataset simulated with FluorMOD and images of wheat in heading stage taken by a ground-based hyperspectral imaging system with 3.3 nm spectral resolution and 0. 71-0.

[Modeling of CO2 fluxes at cropland by using SiB3 model].

The aim is to study the influence of different vegetation types on CO2 fluxes at the same site, taking farmland as the object by using the simple biosphere model (SiB3) , select different vegetation types in Suzhou Dongshan site as input parameters of model to simulate CO2 fluxes, and compare with the observational data in Suzhou Dongshan site during 2011-04-16 to 2011-06-30. Results show that using corn as the site vegetation type input model to simulate CO2 fluxes showed a very good diurnal variation agreement compared to the measured data, but selecting the ordinary crop type input model to simulate CO2 fluxes, CO2 fluxes during the daytime in April and May were undervalued, and CO2 fluxes in June were overvalued; when we select the tea type to input the model, the simulated results significantly overestimated CO2 fluxes during the daytime in May and June. In addition, when using SiB3 model to simulate the daily CO2 fluxes, all three vegetation types input model can effectively simulate daily CO2 fluxes, but not significantly.

[The polarization characteristics distribution and correction method of the polarization coupling error in ocean remote sensing system].

With the development of the quantitative researches using ocean color remote sensing data sets, study on reducing the uncertainty of the response of the ocean color remote sensors to the polarization characteristics of the target has been attracting more and more attention recently. Taking MODIS as an example, the polarization distribution in the whole field of view was analyzed. For the atmosphere path radiance and the apparent radiance considering the coupling between ocean surface and atmosphere, the polarization distribution has a strong relation with the imaging geometry.

Synergy of satellite and ground based observations in estimation of particulate matter in eastern China.

Estimating particulate matter (PM) from space is not straightforward and is mainly achieved using the aerosol optical depth (AOD) retrieved from satellite sensors. However, AOD is a columnar measure, whereas PM is a ground observation. Linking AOD and PM remains a challenge for air pollution monitoring.

[Spatial resolution standardization of payload on board of remote sensing satellite based on application requirements].

Remote sensing application requirements are the starting point for design of payload on board earth observation satellite. The generalization, standardization and serialization of payload are the future development trend for payload design. In the present paper, based on the analysis of remote sensing application requirements, the spatial resolution standardization of satellite remote sensing payload, which is the main concerned indicator, was investigated.

Snow cover monitoring method by using HJ-1 satellite data.

Environment and Disasters Monitoring Microsatellite Constellation with high spatial resolution, high temporal resolution and high spectral resolution characteristics was put forward by China. HJ-1B satellite, one of the first two small optical satellites, had a CCD camera and an infrared camera, which would provide an important new data source for snow monitoring. In the present paper, through analyzing the sensor and data characteristics of HJ-1B, we proposed a new infrared normalized difference snow index (INDSI) referring to the traditional normalized difference snow index (NDSI).

[Analysis of Lop Nur "Ear" features in remote sensing image and its environmental meaning].

There is a great significance of revealing the characteristics of regional environment evolution and global change to the research on arid Lop Nur areas. By the "Ear" features of Lop Nur in remote sensing image, the spectrum, soil and surface parameters were analyzed. The differences in total salt content in soil and the surface structure bring are cause directly for the "Ear" features in remote sensing image; The results of the analysis of spectrum, total salt content and particle size are in good agreement.

[Investigation and assessment of damage in earthquake in Yushu, Qinghai based on multi-spectral remote sensing].

The devastating Yushu Earthquake occurred in Qinghai Province, northwest China, with a magnitude of 7.1 on April 14, 2010, which has caused huge destructive losses. Most buildings along the seismic zone were ruined, especially the old and the basic civil structure houses completely destroyed.

[Retrieval and validation of the surface reflectance using HJ-1-CCD data].

The potentiality of the retrieval of surface reflectance using CCD camera aboard HJ-1A/B satellite was studied. It is very difficult to use dark targets in atmospheric correction due to the lack of near infrared band. The alternative normalized difference vegetation index (NDVI) and the red/blue reflectance ratio are detected from the spectral experiment in Beijing and the Pearl River Delta.

[Fluorescence characteristics of different chlorophyll a concentration in Lake Taihu].

The spectral reflectance and water qualities of 27 stations were acquired in the lake Taihu during the months from May to August, 2008 when blue algal bloomed. Based on the fluorescence characteristics analysis of different chlorophyll a concentration, it was obvious that the position and height of fluorescence peak both have a positive correlation with chlorophyll a concentration, and the correlation coefficients between chlorophyll a concentration and position and half width of fluorescence peak are larger than those of the reference baseline and the normalized height of fluorescence. Estimating of chlorophyll a concentration in case 2 water using fluorescence characteristics is obviously better than the empirical algorithm based on blue to green ratio.

[HJ1A/HSI radiometric calibration and spectrum response function sensitivity analysis].

Hyper spectrum imager (HSI) loaded on HJ-1A satellite is Chinese first spaceborne hyperspectrum sensor. Since the HSI has no spectrum response function of all channels, the usually used calibration method-reflectance based method has been modified, and a new calibration method is proposed, in which the spectrum response function is neglected. Based on the calibration experiment data of Dunhuang in Aug.

[Algorithm of inland water retrieval based on spectral matching].

This present paper presents a new inversion method of inland water based on spectral matching. First step of this method is using the known water surface measured hyperspectral and the absorption coefficient of each component, and obtaining backscattering coefficient of suspended matter with bio-optical model. The second step is calculation of the spectral reflectance of water bodies based on bio-optical model, through the cross-combination of inherent optical property of water components (chlorophyll, suspended matter, yellow substance), in order to create a look-up table of Rrs that corresponds to all combinations of water component.

Evaluation of soil nitrogen emissions from riparian zones coupling simple process-oriented models with remote sensing data.

Riparian ecosystems have critical impacts on controlling the non-point source pollution and maintaining the health of aquatic ecosystems. In this study, a process oriented soil denitrification model was extended with algorithms from a simple nitrogen (N) cycle model and coupled to land surface remote sensing data to enhance its performance in spatial and temporal prediction of gaseous N emissions from soils in the riparian buffer zone surrounding the Guanting reservoir (China). The N emission model is based on chemical and physical relationships that govern the heat budget, soil moisture variations and nitrogen movement in soils.

The novel H1N1 Influenza A global airline transmission and early warning without travel containments.

A novel influenza A (H1N1) has been spreading worldwide. Early studies implied that international air travels might be key cause of a severe potential pandemic without appropriate containments. In this study, early outbreaks in Mexico and some cities of United States were used to estimate the preliminary epidemic parameters by applying adjusted SEIR epidemiological model, indicating transmissibility infectivity of the virus.

[The research on bidirectional reflectance computer simulation of forest canopy at pixel scale].

Computer simulation is based on computer graphics to generate the realistic 3D structure scene of vegetation, and to simulate the canopy regime using radiosity method. In the present paper, the authors expand the computer simulation model to simulate forest canopy bidirectional reflectance at pixel scale. But usually, the trees are complex structures, which are tall and have many branches.

Spatio-temporal distribution of malaria in Yunnan Province, China.

The spatio-temporal distribution pattern of malaria in Yunnan Province, China was studied using a geographic information system technique. Both descriptive and temporal scan statistics revealed seasonal fluctuation in malaria incidences in Yunnan Province with only one peak during 1995-2000, and two apparent peaks from 2001 to 2005. Spatial autocorrelation analysis indicated that malaria incidence was not randomly distributed in the province.

Improving Measurement of Forest Structural Parameters by Co-Registering of High Resolution Aerial Imagery and Low Density LiDAR Data.

Forest structural parameters, such as tree height and crown width, are indispensable for evaluating forest biomass or forest volume. LiDAR is a revolutionary technology for measurement of forest structural parameters, however, the accuracy of crown width extraction is not satisfactory when using a low density LiDAR, especially in high canopy cover forest. We used high resolution aerial imagery with a low density LiDAR system to overcome this shortcoming.

[Multi-layer perceptron neural network based algorithm for simultaneous retrieving temperature and emissivity from hyperspectral FTIR data].

The present paper firstly points out the defect of typical temperature and emissivity separation algorithms when dealing with hyperspectral FTIR data: the conventional temperature and emissivity algorithms can not reproduce correct emissivity value when the difference between the ground-leaving radiance and object's blackbody radiation at its true temperature and the instrument random noise are on the same order, and this phenomenon is very prone to occur rence near 714 and 1 250 cm(-1) in the field measurements. In order to settle this defect, a three-layer perceptron neural network has been introduced into the simultaneous inversion of temperature and emissivity from hyperspectral FTIR data. The soil emissivity spectra from the ASTER spectral library were used to produce the training data, the soil emissivity spectra from the MODIS spectral library were used to produce the test data, and the result of network test shows the MLP is robust.

A bio-optical model based method of estimating total suspended matter of Lake Taihu from near-infrared remote sensing reflectance.

Total suspended matter is an important water quality parameter, and plays a key role in water quality evaluation, especially of inland waters. Many different methods have been developed to estimate TSM from remote sensing data, in which empirical methods and model-based methods are two types of commonly used methods. Compared with empirical methods, model-based methods have the advantages of definite physical meanings, high robustness and retrieval accuracy.

Measurements and simulation of forest leaf area index and net primary productivity in Northern China.

Large scale process-based modeling is a useful approach to estimate distributions of global net primary productivity (NPP). In this paper, in order to validate an existing NPP model with observed data at site level, field experiments were conducted at three sites in northern China. One site is located in Qilian Mountain in Gansu Province, and the other two sites are in Changbaishan Natural Reserve and Dunhua County in Jilin Province.