台风期间海洋飞沫对海气湍通量的影响研究

本文以2006年9月日本以南海域的台风YAGI为例,应用黑潮延伸体附近的KEO浮标观测资料,并结合卫星遥感等融合资料,分析海洋飞沫在台风不同发展阶段对海气界面间热量通量和动量通量的影响。首先,定量地分析台风期间海洋飞沫对海气热通量的影响。结果表明,在台风YAGI过境期间,海洋飞沫能够显著地加剧海气界面间的热量交换,尤其是潜热交换。海洋飞沫增加的热通量随着风速的增强而增大,随着波龄的增大而减小。随后,通过动量分析表明,在台风YAGI过境期间,海洋飞沫显著地增强了由大气向海洋的动量转移。当风速达到台风量级后,考虑海洋飞沫所增加的动量通量与界面动量通量大小相当,同时,在此风速条件下,海洋飞沫在海气界面形成极限饱和悬浮层,抑制风到海表面的动量转移,导致海气界面间总的动量通量的增长率随之减小。     

多环芳烃油指纹应用于船舶溢油鉴别研究

溢油种类主要包括船舶燃料油和原油,二者性质的差异决定了鉴别方法也相应不同,寻求适合于船舶溢油的鉴别方法具有重要意义。在使用柱色谱层析方法对样品进行分离前处理的基础上,以气相色谱/质谱方法(GC-MS)为主要分析手段,对溢油样品和可疑船舶溢油源样品的多环芳烃油指纹特征进行对比,并在多环芳烃油指纹参数的基础上进一步进行多环芳烃内组成三角图分布特征与聚类分析研究,成功为珠江口水域某船舶溢油事故追踪到肇事溢油源。结果表明:取自丁船的油样和现场溢油样芳烃油指纹特征最为相近,是此次溢油事故的溢油源。受风化作用后的船舶燃料油中饱和烃类化合物数量稀少,且含量极低,不适合用于溢油鉴别,而多环芳烃类化合物较饱和烃类化合物而言具有含量高、种类丰富的特点,是该类溢油鉴别的主要油指纹依据。使用油指纹参数进行可疑溢油源识别时,充分考虑油品中有机分子所受风化影响程度的不同是风化条件下溢油鉴定的关键。因此,多环芳烃油指纹可以有效应用于船舶燃料油溢油的鉴别。     

Multifractal detrended fluctuation analysis of the δ 18 O record of NGRIP ice core

The multifractal properties and scaling behaviors of the long-term and recent 2000-year δ ¹⁸ O records of NGRIP ice core are investigated by the multifractal detrended fluctuation analysis method. The generalized Hurst exponents, multifractal scaling exponents, and singularity spectrums of two δ ¹⁸ O records are derived to verify the multifractiality of two records. And the multifractal behaviors of two records are obviously different, which may reflect the climate change of the recent 2000-year time is quite different from one of the long-term time. In addition, the probability distribution analysis of two δ ¹⁸ O records is presented to manifest the different multifractality between two δ ¹⁸ O records of NGRIP ice core. Our results will be helpful to research the climate change.     

Multimodel ensemble projections of future climate extreme changes in the Haihe River Basin,China

Exploring the characteristic of the extreme climatic events, especially future projection is considerably important in assessing the impacts of climatic change on hydrology and water resources system. We investigate the future patterns of climate extremes (2001–2099) in the Haihe River Basin (HRB) derived from Coupled General Circulation Model (CGCM) multimodel ensemble projections using the Bayesian Model Average (BMA) approach, under a range of emission scenarios. The extremes are depicted by three extreme temperature indices (i.e., frost days (FD), growing season length (GSL), and T _min >90th percentile (TN90)) and five extreme precipitation indices (i.e., consecutive dry days (CDD), precipitation ≥10 mm (R10), maximum 5-day precipitation total (R5D), precipitation >95th percentile (R95T), and simple daily intensity index (SDII)). The results indicate frost days display negative trend over the HRB in the 21st century, particularly in the southern basin. Moreover, a greater season length and more frequent warm nights are also projected in the basin. The decreasing CDD, together with the increasing R10, R5D, R95T, and SDII in the 21st century indicate that the extreme precipitation events will increase in their intensity and frequency in the basin. Meanwhile, the changes of all eight extremes climate indices under A2 and A1B scenarios are more pronounced than in B1. The results will be of practical significance in mitigation of the detrimental effects of variations of climatic extremes and improve the regional strategy for water resource and eco-environment management, particularly for the HRB characterized by the severe water shortages and fragile ecological environment.     

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Analgesis and wound healing effect of chitosan and carboxymethyl chitosan on scalded rats

Analgesis and wound healing effect of chitosan and carboxymethyl chitosan on scalded rats were investigated. A II degree scald model was established in rats, which was subsequently treated with chitosan and carboxymethyl chitosan solution, respectively. The concentration of bradykinin and 5-hydroxytryptophan was detected by assaying enzyme-linked immunosorbent. Healing condition was observed and pathological sections were made to determine the healing effect of chitosan and carboxymethyl chitosan. Results showed that the concentration of bradykinin and 5-hydroxytryptophan peaked at the third hour post-wound in all groups, while the concentration of hydroxyproline peaked at the seventh day post-wound in both chitosan and carboxymethyl chitosan group. The concentration of bradykinin and 5-hydroxytryptophan of carboxymethyl chitosan group was significantly lower than that of control (P < 0.05), while that of chitosan group was similar to that of control (P > 0.05). These findings indicated that carboxymethyl chitosan reduced the concentration of algogenic substances, resulting in analgesia. During the whole recovery process, the hydroxyproline concentration in chitosan and carboxymethyl chitosan group on day 3 and 7 was significantly higher than that of control (P < 0.01); however the significance of such a highness decreased on day 14 (P < 0.05). These findings indicated that chitosan and carboxymethyl chitosan accelerated tissue repair. Meanwhile, chitosan performed better in healing than carboxymethyl chitosan in both decrustation and healing time. In conclusion, carboxymethyl chitosan showed significant analgesis and wound-healing promotion effect, but chitosan only showed wound-healing promotion effect.     

Response of diatom community in Lugu Lake (Yunnan–Guizhou Plateau,China) to climate change over the past century

A mean annual temperature increase has been recorded on the Yunnan–Guizhou Plateau of China during the last century. This temperature increase has been significantly greater since the 1950s. Thus, paleolimnological analyses may be utilized to better understand ecological responses to recent changing climate over decadal to centennial timescales, especially in regions with sparse lake monitoring data. Here, we present paleolimnological results from a ²¹⁰Pb/¹³⁷Cs-dated sediment core spanning approximately the last ~250 years from a remote, alpine, semi-closed oligotrophic lake (Lugu Lake) on the northwestern Yunnan–Guizhou Plateau. Sediment profiles of diatoms, geochemical variables (LOI₅₅₀, TOC and C/N) and median grain size were analyzed and compared with the climate data (1951 AD–2010 AD) from the Lijiang weather station. Endogenous productivity of Lugu Lake has increased gradually over the last 30 years. The majority of diatom taxa encountered in the core are typical of alkaline oligotrophic lakes. Diatom assemblages were dominated by Cyclostephanos dubius, Cyclotella taxa, and fragilarioid taxa. Diatom species composition has changed significantly with three assemblage shifts at different scales over the ~250-year period. Diatom species diversity reveals a distinct increase before ~1970 AD, followed by a decline. In addition, a decreasing trend in diatom cell-size was consistent with recent warming trends. Redundancy analysis (RDA) shows that regional air temperature trends (annual, spring, summer, and winter) have played a significant role (p < 0.05) in determining diatom compositional changes over the past six decades. Results of this study suggest that regional warming is the main driving force behind recent changes in diatom composition at Lugu Lake, while nutrients may also have impact on the diatom change in recent 10 years.     

Statistical characteristics and mechanisms of mesoscale eddies in the North Indian Ocean

The statistical characteristics and mechanisms of mesoscale eddies in the North Indian Ocean are investigated by adopting multi-sensor satellite data from 1993 to 2019. In the Arabian Sea(AS), seasonal variation of eddy characteristics is remarkable, while the intraseasonal variability caused by planetary waves is crucial in the Bay of Bengal(BOB). Seasonal variation of the eddy kinetic energy(EKE) is distinct along the west boundary of AS,especially in the Somali Current region. In the BOB, lar...     

伶仃洋夏季叶绿素a时间变化特征及分析

文章使用2019年7月5日—20日在珠江河口伶仃洋定点连续观测的海表面叶绿素a质量浓度、海表面气温、气压、风速、风向、海表温度、盐度、流速、流向、遥感降雨量数据和中等分辨率成像光谱仪可见光波段影像, 利用小波分析和集成经验模态分解方法分析了观测期间内伶仃洋海表面叶绿素a的时间变化特征及其影响因子。分析结果表明, 观测期间海水表层叶绿素a质量浓度的变化范围为0.44~1.75µg·L^-1, 平均值为0.80µg·L^-1, 其变化周期主要为6h、12h和24h。其与相对应周期的潮流存在明显的相位关系, 并且在降雨后两者的相位关系发生了转换。7月5日—12日, 叶绿素a与潮流基本呈反相位关系, 涨急时叶绿素a质量浓度低, 落急时叶绿素a质量浓度较高, 浓度相差约为0.3µg·L^-1。珠江流域在7月8日—13日发生了一次强降雨过程, 降雨前后海水表层叶绿素a质量浓度在6h、12h和24h周期波段的振幅由0.02~0.09µg·L^-1增加到0.15µg·L^-1左右。同时, 降雨对珠江河口的叶绿素a质量浓度造成了一个持续80h的增加过程, 浓度增加了0.3µg·L^-1。发生降雨后, 7月13日—20日期间潮流滞后于叶绿素a约6h, 水位最高时叶绿素a质量浓度最低, 水位最低时叶绿素a质量浓度最高。由以上结果可以看出, 降雨不仅引起了河口区叶绿素a质量浓度的增加, 还造成了叶绿素a和潮流间相位关系的转换。     

Regional ecosystem services relationships and their potential driving factors in the Yellow River Basin,China

The Yellow River Basin(YRB) occupies an important position in China’s socioeconomic development and ecological conservation efforts. Understanding the spatiotemporal characteristics of the relationships among multiple ecosystem services(ESs) and their drivers is crucial for regional sustainable development and human-earth system coordination. This study simulated food production(FP), water yield(WY), net primary production(NPP), soil conservation(SC), and habitat quality(HQ) in the YRB from 2000...