Simulation of the Ecosystem Productivity Responses to Aerosol Diffuse Radiation Fertilization Effects over the Pan-Arctic during 2001–19

The pan-Arctic is confronted with air pollution transported from lower latitudes.Observations have shown that aerosols help increase plant photosynthesis through the diffuse radiation fertilization effects(DRFEs).While such DRFEs have been explored at low to middle latitudes,the aerosol impacts on pan-Arctic ecosystems and the contributions by anthropogenic and natural emission sources remain less quantified.Here,we perform regional simulations at 0.2o×0.2ousing a well-validated vegetation model(Yale Interactive terrestrial Biosphere,YIBs)in combination with multi-source of observations to quantify the impacts of aerosol DRFEs on the net primary productivity(NPP)in the pan-Arctic during 2001-19.Results show that aerosol DRFEs increase pan-Arctic NPP by 2.19 Pg C(12.8%)yr^(-1)under clear-sky conditions,in which natural and anthropogenic sources contribute to 8.9% and 3.9%,respectively.Under all-sky conditions,such DRFEs are largely dampened by cloud to only 0.26 Pg C(1.24%)yr^(-1),with contributions of 0.65% by natural and 0.59% by anthropogenic species.Natural aerosols cause a positive NPP trend of 0.022% yr^(-1)following the increased fire activities in the pan-Arctic.In contrast,anthropogenic aerosols induce a negative trend of-0.01% yr^(-1)due to reduced emissions from the middle latitudes.Such trends in aerosol DRFEs show a turning point in the year of 2007 with more positive NPP trends by natural aerosols but negative NPP trends by anthropogenic aerosols thereafter.Though affected by modeling uncertainties,this study suggests a likely increasing impact of aerosols on terrestrial ecosystems in the pan-Arctic under global warming.

Climatic drivers of the Canadian wildfire episode in 2023

2023年5月加拿大发生极端野火事件并持续4个月时间.野火污染物排放对当地和下风向的空气质量造成了严重影响.本文对驱动此次野火事件的气象因子和相关大尺度环流进行了探究.研究表明,此次极端野火排放的二氧化碳相较往年同期增长了0.37Gt (527.1%).受罗斯贝波频散影响,同期加拿大中西部区域出现持续的位势高度正异常,促进气流下沉并引发局地高温,中西部区域5-6月最高温平均上升8.11℃,部分区域甚至超过10℃,导致野火排放的显著增长.受有利地形和泛北极地区快速增暖的影响,预期未来加拿大中西部发生极端野火的概率可能会显著上升.

Clinical Outcome of Internal Fixation and Fusion in the Treatment of Spinal Fractures by Paraspinal Muscular Space Approach

Objective:To explore the clinical effect of internal fixation and fusion with the paraspinal muscle gap approach in the treatment of spinal fracture patients.Methods:104 spinal fracture patients admitted to Central Hospital of TCM from October 2022 to April 2024 were selected as the study subjects and were randomly divided into the control group(n=52)and the observation group(n=52)according to the random number table method.The control group was treated with the conventional approach of internal fixation surgery,and the observation group was treated with the paraspinal muscular interspace approach of internal fixation fusion.The two groups’general data,surgical indexes,pain,lumbar spine function,and postoperative complications were observed.Results:The baseline data of the two groups of patients were not statistically significant(all P>0.05)while the intraoperative bleeding,the first postoperative time getting up from bed,and the length of hospital stay of the patients in the observation group were shorter than that of the control group(all P=0.000<0.001),and the duration of the operation was longer than that of the control group(t=2.644,P=0.010<0.05);at 3 months postoperatively,the VAS scores of the patients in the observation group were significantly lower than those in the control group(t=10.768,P=0.000<0.001),and the JOA score was higher than that of the control group(t=6.498,P=0.000<0.001);the total complication rate of patients in the observation group(3/5.77%)was significantly lower than that of the control group(12/23.08%)(χ^(2)=6.310,P=0.012<0.05).Conclusion:In the treatment of spinal fracture patients,compared with the conventional approach to internal fixation surgery,the paraspinal muscular gap approach to internal fixation and fusion treatment is less traumatic,postoperative lumbar spine function recovery is faster,and can reduce the incidence of postoperative complications.

Multimodel ensemble projection of photovoltaic power potential in China by the 2060s

为了实现能源转型的目标,中国对太阳能的需求一直在极速增长.然而,太阳能发电潜力受到天气条件的影响并预期在气候变暖背景下发生改变.本文中,作者利用第六次国际耦合模式比较计划(CMIP6)24个气候模式的气象变量以及4个不同形式的光伏模型,预估了在2060年代低排放或高排放情况下中国的光伏发电潜力.多模式集合平均光伏功率在2004-2014年为277.2KWhm-2yr-1,并呈现出从西到东的下降趋势.到2054-2064年,在低排放情景下,全国平均光伏发电潜力将增加2.29%,而在高排放情景下则减少0.43%.低排放情景的排放控制大大增强了地表太阳辐射,促进了东部的光伏发电.相反,在高排放情景下,强烈的变暖对光伏发电产生了抑制作用.极端暖事件使光伏发电潜力在低排放情景下降低0.28%,而高排放情景下降低0.44%,分别相当于当代损失量的两倍和三倍.预估表明排放控制带来的清洁空气和适度变暖对中国未来的太阳能利用是有益的.

Comparison of Ozone and PM2.5 Concentrations over Urban,Suburban,and Background Sites in China

Surface ozone(O3)and fine particulate matter(PM2.5)are dominant air pollutants in China.Concentrations of these pollutants can show significant differences between urban and nonurban areas.However,such contrast has never been explored on the country level.This study investigates the spatiotemporal characteristics of urban-to-suburban and urban-tobackground difference for O3(Δ[O3])and PM2.5(Δ[PM2.5])concentrations in China using monitoring data from 1171 urban,110 suburban,and 15 background sites built by the China National Environmental Monitoring Center(CNEMC).On the annual mean basis,the urban-to-suburbanΔ[O3]is−3.7 ppbv in Beijing-Tianjin-Hebei,1.0 ppbv in the Yangtze River Delta,−3.5 ppbv in the Pearl River Delta,and−3.8 ppbv in the Sichuan Basin.On the contrary,the urban-to-suburbanΔ[PM2.5]is 15.8,−0.3,3.5 and 2.4μg m^−3 in those areas,respectively.The urban-to-suburban contrast is more significant in winter for bothΔ[O3]andΔ[PM2.5].In eastern China,urban-to-background differences are also moderate during summer,with−5.1 to 6.8 ppbv forΔ[O3]and−0.1 to 22.5μg m^−3 forΔ[PM2.5].However,such contrasts are much larger in winter,with−22.2 to 5.5 ppbv forΔ[O3]and 3.1 to 82.3μg m^−3 forΔ[PM2.5].Since the urban region accounts for only 2%of the whole country’s area,the urban-dominant air quality data from the CNEMC network may overestimate winter[PM2.5]but underestimate winter[O3]over the vast domain of China.The study suggests that the CNEMC monitoring data should be used with caution for evaluating chemical models and assessing ecosystem health,which require more data outside urban areas.

Increasing impacts of fire air pollution on public and ecosystem health

Wildfire episodes have become more frequent and severe in recent years.1 Record-breaking fires devastated the Arctic,Amazon,and Australia in 2019–2020.This year,fires began in Canada in May and lasted for several months,resulting in an area burned of 16.5 million hectares by early September.This size is 6–7 times the annual fire area for a normal year in Canada.The favorable fire weather for burning and spread lasted for months(https://cwfis.cfs.nrcan.gc.ca/maps/fw).Furthermore,most Canadian fires occur in remote regions far from firefighting facilities,causing fire extinction to be difficult.Unfortunately,such“unprecedented”fire events occurred routinely in boreal regions between 2020 and 2023,although the locations varied from year to year(Figure 1).