Separation Of Soil Evaporation And Vegetation Transpiration By MODIS Data For Central And Northern China

Evapotranspiration(ET) plays a crucial role in the hydrologic system. To estimate evapotranspiration quantitatively in a large scale, remote sensing data has been used in a number of models and shows its applicability in the estimation of evapotranspiration. In this paper, evapotranspiration for central and northern China was derived from MODIS data. In arid and semi-arid regions, soil evaporation can be considered as the minimum water requirement for bare area, while evapotranspiration can be considered as the minimum water demand for the area covered by vegetation. Hence the separation of soil evaporation and vegetation transpiration is valuable for efficient water resources management. In this study, the land surface temperature-fractional vegetation coverage(Ts-f) trapezoid method was applied in conjunction with an operational two-layer model. A modified algorithm for the determination of actual dry/wet edges(MADE) of the Ts-f trapezoid was proposed, which is an improvement of the original method based on Ts-VI(vegetation index) triangle developed by Ronglin Tang(2010). The MADE algorithm was then integrated with the two-layer model to estimate the latent heat flux (evaporation and transpiration). It’s showed that the retrieved latent heat flux is in good agreement with FLUXNET data obtained from Department of Biogeochemical Integration. The root mean square error of monthly ET is below 25 W/m2. The result demonstrated that the accuracy of the modified algorithm to determine dry/wet edges in the Ts-f trapezoid was satisfactory. Finally, the spatial and temporal distribution of soil evaporation and vegetation transpiration of central and northern China was further investigated in this study

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Addressing the climate challenge

In 2021, colleagues from across the University of Birmingham community were invited to write articles about topics relevant to the COP26 climate change summit. In this series of articles, experts from across many different disciplines provide new insight and evidence on how we might all understand and tackle climate change

Sustainability Risks of Coastal Cities from Climate Change

 Issues influencing the sustainability of coastal cities are assessed, reflecting the combination of impending sea level rise and storm surges, and increasing growth in populations in coastal cities. Geologic-time scales are utilized to draw parallels to characterize relevant historical occurrences that help to understand the context of projections of impending sea level rise issue to year 2100. Given that Antarctica holds sufficient water to raise global sea levels by 58 m if the ice were to melt, this indicates that even a small percentage of melting of the polar ice caps, should this occur, will have enormous implications to the sustainability of coastal cities which are projected to hold 12.4 percent of the world’s population by 2060. The result is the combination of predicted sea level rise and associated storm surges indicate that drastic measures must be promoted to improve the sustainability of coastal cities

Sustainability Risks of Coastal Cities from Climate Change

 Issues influencing the sustainability of coastal cities are assessed, reflecting the combination of impending sea level rise and storm surges, and increasing growth in populations in coastal cities. Geologic-time scales are utilized to draw parallels to characterize relevant historical occurrences that help to understand the context of projections of impending sea level rise issue to year 2100. Given that Antarctica holds sufficient water to raise global sea levels by 58 m if the ice were to melt, this indicates that even a small percentage of melting of the polar ice caps, should this occur, will have enormous implications to the sustainability of coastal cities which are projected to hold 12.4 percent of the world’s population by 2060. The result is the combination of predicted sea level rise and associated storm surges indicate that drastic measures must be promoted to improve the sustainability of coastal cities

Fabrication of bead-on-string polyacrylonitrile nanofibrous air filters with superior filtration efficiency and ultralow pressure drop

The presence of ultrafine particle matter (PM) in air is one of the most hazardous environmental issues because of their severe threat to human health. Design and development of cost-effective and energy-efficient air filters to remove the PM by facile methods are highly demanded. Electrospun nanofibrous membranes have been explored for PM filtrations as they can achieve high removal efficiencies due to their ultrafine nanofibers. However, their enhanced particle removal efficiencies are at the cost of high pressure drops. In this work, porous bead-on-string filters with nanobeads along the nanofiber axis have been successfully fabricated by optimizing the polyacrylonitrile (PAN) concentration of electrospun dopes and ambient humidity condition during the electrospinning process. The combined effects of polymer concentration and humidity condition could achieve an unbalanced status between the repulsive and constrictive forces along the jets from the spinneret in the electrospinning process, which generated a filter with a desirable bead-on-string morphology. The nanobeads are able to reduce the packing density and alleviate the pressure drop through the filter while the ultrafine nanofibers guarantee the PM removal efficiency. Besides, the effects of nanofiber diameter, airflow rate and nanobead density on the filtration efficiency and pressure drop of NaCl solid and Paraffin oil aerosols with an average diameter of 300 nm have been investigated systematically. With the assistance of bead-on-string construction, the pristine PAN filter can easily achieve an excellent efficiency above 99% with a low pressure drop of 27 Pa at an airflow rate of 4.2 cm/s. This work suggests that transformation of electrospun filters from a nanofibrous structure to a bead-on-string morphology via the adjustments of polymer concentration and ambient humidity is sufficient to generate filter mediums with excellent efficiency and low airflow resistance for air filtration applications, which is also facile to be scaled up as no special equipment and costly chemicals are required.This work was supported by the National Key Research and Development Program of China (2016YFC0400709), National Science Foundation of Tianjin (18JCYBJC41900), National Natural Science Foundation of China (21906086), the Fundamental Research Funds for the Central Universities, Nankai University (040-63191433)

Comprehensive comparison performances of Landsat-8 atmospheric correction methods for inland and coastal waters

Atmospheric correction (AC) is a crucial step in the quantitative analysis of inland and coastal waters. In this study, the performances of six water-based AC methods (SeaDAS, ACOLITE-DSF/EXP, C2RCC, iCOR) were evaluated by using multiple global datasets (N = 139). Four evaluation strategies were applied including spectral similarity and Chlorophyll-a retrieval. The results showed that SeaDAS and ACOLITE-DSF performed the best in terms of analytical match, band ratios, Chlorophyll-a retrieval, and spectral similarity. SeaDAS had the lowest RMSE in the blue-green bands and showed good consistency across the spectral with the lowest median spectral angle of 7°. It should be noted that ACOLITE-DSF outperforms SeaDAS in high turbidity waters. SeaDAS coupled with Chlorophyll-a retrieval algorithms of OC3 and Clark had the lowest RMSE, which showed the advantage of SeaDAS in Chlorophyll-a retrieval. This study provides scientific basis for choosing AC methods of Landsat-8 data for aquatic environment monitoring