Characteristics of Surface Solar Radiation under Different Air Pollution Conditions over Nanjing, China: Observation and Simulation

Surface solar radiation (SSR) can affect climate, the hydrological cycle, plant photosynthesis, and solar power. The values of solar radiation at the surface reflect the influence of human activity on radiative climate and environmental effects, so it is a key parameter in the evaluation of climate change and air pollution due to anthropogenic disturbances. This study presents the characteristics of the SSR variation in Nanjing, China, from March 2016 to June 2017, using a combined set of pyranometer and pyrheliometer observations. The SSR seasonal variation and statistical properties are investigated and characterized under different air pollution levels and visibilities. We discuss seasonal variations in visibility, air quality index (AQI), particulate matter (PM10 and PM2.5), and their correlations with SSR. The scattering of solar radiation by particulate matter varies significantly with particle size. Compared with the particulate matter with aerodynamic diameter between 2.5 μm and 10 μm (PM2.5-10), we found that the PM2.5 dominates the variation of scattered radiation due to the differences of single-scattering albedo and phase function. Because of the correlation between PM2.5 and SSR, it is an effective and direct method to estimate PM2.5 by the value of SSR, or vice versa to obtain the SSR by the value of PM2.5. Under clear-sky conditions (clearness index ≥0.5), the visibility is negatively correlated with the diffuse fraction, AQI, PM10, and PM2.5, and their correlation coefficients are ?0.50,?0.60,?0.76, and ?0.92, respectively. The results indicate the linkage between scattered radiation and air quality through the value of visibility.

Early diagenesis of redox-sensitive trace metals in the northern Okinawa Trough

The early diagenesis processes of several redox-sensitive trace metals(RSMs)(Mo, U and V) were studied with several short sediment cores(~25 cm) collected in the northern Okinawa Trough(OT). Pore water vertical profiles indicated that the sedimentary environments in all cores were between oxic and suboxic, not yet reaching anoxic sulfidic conditions. The recycling process of Mo in sediments was clearly associated with Mn and yielded little authigenic accumulation, while U showed a downcore increase in sediment and its authigenic mass accumulation rate(MAR) was estimated to be ~23% of the Changjiang(Yangtze) and Huanghe(Yellow) riverine flux. Benthic diffusive fluxes and MAR were calculated and the comparison of them showed that U and V fluxes matched relatively well both in direction and in magnitude, implying that diffusion processes at the sedimentwater interface is the dominant process controlling the remobilization or burial of V and U in northern OT. This work provided a systematic study(both in pore water and solid phase) on the RSMs geochemical behaviors during early diagenesis process, yielding a quantitative assessment of the remobilization or burial fluxes of the RSMs in northern OT. Such studies are in general lacking in the coastal margin of Northwest Pacific Ocean.

A New Analysis Method for Locating the Focus and for Estimating the Size of the Focus of the Backscatter Light of a LIDAR System

This paper presents a new analysis method for locating the focus and estimating the size of the focus of the backscatter light of a Lidar system. The formula for calculating the uncertainty of the location of the focus of backscatter light of a Lidar system is given, and the estimation of the size of the focus is also presented. This calculation coincides with the analysis result of ZEMAX software. By the analysis, the experiment to exactly locate the focus of the backscatter light of Lidar is carried out.

轻中度阿尔茨海默病患者肌肉力量与认知功能、内侧颞叶萎缩的相关性

目的分析轻中度阿尔茨海默病(AD)患者肌肉力量与认知功能、内侧颞叶萎缩(MTA)间的相关性。方法选取2021年1—12月在苏州大学附属第二医院神经内科记忆障碍门诊确诊的80例AD患者(轻度41例,中度39例)和同期体检中心体检的43名对照者(NC),收集一般资料、肌少症相关指标、神经心理学测试与MTA评分。肌少症相关指标中四肢骨骼肌量指数(ASMI)评估肌肉量,握力与5次起坐时间评估肌肉力量,6 m步速评估躯体功能。认知功能量表为简易精神状态量表(MMSE)、蒙特利尔认知评估量表(MoCA)、记忆与执行功能筛查量表(MES)、数字符号转换测验(DSST)、数字广度测试(DST)、词语流畅性试验(VFT),DST包括顺序(FDST)和倒序(BDST)。受试者均行3.0 T颅脑冠状位三维梯度回波序列磁共振检查,MTA量表评估内侧颞叶萎缩程度。分析三组肌少症相关指标、认知评分、MTA评分间的差异,并且两两之间进行偏相关分析。结果80例AD患者,男24例、女56例,年龄(72±7)岁,其中轻度AD患者41例,中度AD患者39例;43名NC,男19名、女24名,年龄(70±6)岁。中度AD组病程长于轻度AD组[34.0(25.0,43.5)个月比24.0(11.0,34.0)个月,P<0.001]。三组肌少症相关指标及MTA评分比较,组间差异均有统计学意义(均P<0.001),如5次起坐时间[(13.6±1.8)s比(11.5±1.7)s比(10.3±1.9)s,P<0.001],MTA评分[2.0(2.0,3.0)分比1.0(1.0,2.0)分比0(0,0)分,P<0.001]。神经心理学测试中,轻、中度AD组MMSE、MoCA、MES、VFT得分均低于NC组,且中度AD组低于轻度AD组(均P<0.001)。AD组肌少症相关指标中,尤其是肌肉力量,与多个认知功能领域和MTA评分相关。握力与MMSE、MoCA、MES、FDST(r=0.387、0.418、0.522、0.484,均P<0.001)、DSST(r=0.327,P=0.006)、VFT得分(r=0.354,P=0.003)呈正相关,与MTA评分(r=-0.631,P<0.001)呈负相关;5次起坐时间与MMSE、MoCA、MES、DSST、FDST、VFT(r=-0.583、-0.587、-0.814、-0.591、-0.552、-0.485,均P<0.001)、BDST(r=-0.355,P=0.003)得分呈负相关,与MTA评分(r=0.836,P<0.001)呈正相关;ASMI与MMSE、MoCA、MES、DSST、FDST得分(r=0.257、0.238、0.428、0.282、0.364,均P<0.05)呈正相关,与MTA评分(r=-0.377,P=0.001)呈负相关;6 m步速与MMSE、MoCA、MES、DSST、FDST(r=0.419、0.486、0.699、0.559、0.500,均P<0.001)、BDST和VFT得分(r=0.384、0.377,均P=0.001)呈正相关,与MTA评分(r=-0.803,P<0.001)呈负相关。结论轻中度AD患者认知功能广泛性受损,肌肉量、肌肉力量、躯体功能均明显减退。相较肌肉量与躯体功能,肌肉力量下降与广泛性认知功能减退和MTA程度增加显著相关。

Identification of close relationship between atmospheric oxidation and ozone formation regimes in a photochemically active region

Understanding ozone(O_(3))formation regime is a prerequisite in formulating an effective O_(3)pollution control strategy.Photochemical indicator is a simple and direct method in identifying O_(3)formation regimes.Most used indicators are derived from observations,whereas the role of atmospheric oxidation is not in consideration,which is the core driver of O_(3)formation.Thus,it may impact accuracy in signaling O_(3)formation regimes.In this study,an advanced three-dimensional numerical modeling system was used to investigate the relationship between atmospheric oxidation and O_(3)formation regimes during a long-lasting O_(3)exceedance event in September 2017 over the Pearl River Delta(PRD)of China.We discovered a clear relationship between atmospheric oxidative capacity and O_(3)formation regime.Over eastern PRD,O_(3)formation was mainly in a NO x-limited regime when HO_(2)/OH ratio was higher than 11,while in a VOC-limited regime when the ratio was lower than 9.5.Over central and western PRD,an HO_(2)/OH ratio higher than 5 and lower than 2 was indicative of NO x-limited and VOC-limited regime,respectively.Physical contribution,including horizontal transport and vertical transport,may pose uncertainties on the indication of O_(3)formation regime by HO_(2)/OH ratio.In comparison with other commonly used photochemical indicators,HO_(2)/OH ratio had the best performance in differentiating O_(3)formation regimes.This study highlighted the necessities in using an atmospheric oxidative capacity-based indicator to infer O_(3)formation regime,and underscored the importance of characterizing behaviors of radicals to gain insight in atmospheric processes leading to O_(3)pollution over a photochemically active region.

Benthic foraminiferal δ^(13)C minimum events in the southeastern Okhotsk Sea over the last 180 ka

A total of six d13C minimum events,i.e.,VI,V,IV,III,II,and I,were observed via a stable carbon and oxygen isotope analysis of infaunal benthic foraminifera Uvigerina spp.in gravity core OS03-1 in the southeastern Okhotsk Sea over the last 180 ka.These events occurred at112–109,102–90,85–76,57–54,44–40,and 17–10 ka BP.The largest negative excursions reached 2.5%in event V and were greater than 1%in the other events.We proposed that all d13C minimum events were caused by the increase in sea surface water productivity,the weakened formation of Okhotsk Sea intermediate water,and the enhancement of the oxygen minimum zone.The negative excursions were unaffected by methane hydrate destabilization and subsequent methane release based on the results obtained by using archaeal lipid markers.