2023年塔吉克斯坦M_(W)7.2地震InSAR同震形变场与滑动分布

利用Sentinel-1A卫星SAR影像数据,对2023年塔吉克斯坦M_(W)7.2地震开展同震形变提取,基于弹性位错模型进行断层反演,并以本文反演得到的右旋节面解为接收面,计算不同深度的静态库仑应力。同震形变结果显示,升轨LOS向最大形变量达15 cm,降轨LOS向最大形变量达16 cm。断层反演结果表明,此次地震最优发震断层走向为131.1°、倾角为85.7°,同震主滑移区分布在深度10~30 km范围内,以右旋走滑为主,最大滑移位置位于地下约20 km深度处,滑移量为3.49 m,未破裂至地表,矩震级为M_(W)7.16。库仑应力结果显示,该区域库仑应力符合帕米尔高原已有的应力场及地质学研究结果,随着深度增加,其影响范围以发震断层为中心向外扩张,且自5 km深度往下,应力加载区逐渐侵蚀应力卸载区,并开始以加载区为主,在约10 km深度处开始发生余震活动,与本次发震断层相邻的2条断层未来短时间内地震风险性较小。

Projected Regional 1.50℃and 2.00℃Warming Threshold-crossing Time Worldwide Using the CMIP6 Models

The Paris Agreement aims to limit global warming to well below 2.00℃and pursue efforts to limit the temperature increase to 1.50℃.However,the response of climate change to unbalanced global warming is affected by spatial and temporal sensitivities.To better understand the regional warming response to global warming at 1.50℃and 2.00℃,we detected the 1.50℃and 2.00℃warming threshold-crossing time(WTT)above pre-industrial levels globally using the Coupled Model Intercomparison Project phase 6(CMIP6)models.Our findings indicate that the 1.50℃or 2.00℃WTT differs substantially worldwide.The warming rate of land would be approximately 1.35–1.46 times that of the ocean between 60°N–60°S in 2015–2100.Consequently,the land would experience a 1.50℃(2.00℃)warming at least 10–20 yr earlier than the time when the global mean near-surface air temperature reaches 1.50℃(2.00℃)WTT.Meanwhile,the Southern Ocean between 0°and 60°S considerably slows down the global 1.50℃and 2.00℃WTT.In 2040–2060,over 98.70%(77.50%),99.70%(89.30%),99.80%(93.40%),and 100.00%(98.00%)of the land will have warmed by over 1.50℃(2.00℃)under SSP(Shared Socioeconomic Pathway)1–2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5,respectively.We conclude that regional 1.50℃(2.00℃)WTT should be fully considered,especially in vulnerable high-latitude and high-altitude regions.

Changes of heating and cooling degree days over China in response toglobal warming of 1.5℃, 2℃, 3℃ and 4℃

Future changes of heating degree days （HDD） and cooling degree days （CDD） in the 21st century with and without considering populationfactor are investigated based on four sets of climate change simulations over East Asia using the regional climate model version 4.4 （RegCM4.4）driven by the global models of CSIRO-Mk3-6-0, EC-EARTH, HadGEM2-ES, and MPI-ESM-MR. Under global warming of 1.5℃, 2℃, 3℃,and 4℃, significant decrease of HDD can be found over China without considering population factor, with greater decrease over high elevationand high latitude regions, including the Tibetan Plateau, the northern part of Northeast China, and Northwest China; while population-weightedHDD increased in areas where population will increase in the future, such as Beijing, Tianjin, parts of southern Hebei, northern Shandong andHenan provinces. Similarly, the CDD projections with and without considering population factor are largely different. Specifically, withoutconsidering population, increase of CDD were observed over most parts of China except the Tibetan Plateau where the CDD remained zerobecause of the cold climate even under global warming; while considering population factor, the future CDD decreases in South China andincreases in North China, the Sichuan Basin, and the southeastern coastal areas, which is directly related to the population changes. The differentfuture changes of HDD and CDD when considering and disregarding the effects of population show that population distribution plays animportant role in energy consumption, which should be considered in future research.

China＇s low-carbon investment pathway under the 2℃ scenario

The generally adopted worldwide target is to keep the increase in the global mean temperature lower than 2C by 2100, which is comparable with that of the preindustrial era. It is feasible for China to realize an emission pathway that is consistent with this target; however, we need to understand the roadmap to do so. In this paper, the results of a modeling study by the Integrated Policy Assessment Model for China(IPAC)concerning the investment required to realize the 2℃ scenario by examining the penetration of low-carbon technologies including energy supply and energy efficiency improvement in end-use sectors is presented. It is found that the investment required in the energy supply sector to realize the 2C scenario could reach CN$1.2 trillion by 2020, CN$1.0 trillion by 2030, and CN$1.4 trillion by 2050. The investment needed for energy saving could reach CN$1.6 trillion by 2020, CN$1.8 trillion by 2030, and CN$1.5 trillion by 2050, which represents the additional investment as compared with the use of old technologies. If the investment required both in the energy supply sector and in energy saving in enduse sectors is considered, the total investment is estimated to be CN$2.8 trillion by 2020, CN$2.8 trillion by 2030, and CN$2.9 trillion by 2050.These investments account for 2.5% of China's total GDP in 2020, 1.3% in 2030, and 0.6% by 2050, which represents quite a small investment percentage to realize the goal of low-carbon development.

Impact of Thickness of Polymer Electrolyte Membrane and Gas Diffusion Layer on Temperature Distributions in Polymer Electrolyte Fuel Cell Operated at Temperature around 90℃

Polymer Electrolyte Fuel Cell(PEFC)is desired to be operated at temperature around 90℃ for stationary applications during the period from 2020 to 2025 in Japan.It can be expected thinner polymer electrolyte membrane(PEM)and gas diffusion layer(GDL)would promote the power generation performance of PEFC at this temperature.The aim of this study is to understand the impact of thickness of PEM and GDL on the temperature profile of interface between PEM and catalyst layer at the cathode(i.e.,the reaction surface)in a single PEFC with an initial operation temperature(Tini).An 1D multi-plate heat transfer model based on temperature data of separator measured using thermograph in power generation process was developed to evaluate temperature of the reaction surface(Treact).This study investigated the effect of Tini,flow rate and relative humidity of supply gas on Treact distribution.The study finds that when using thin GDL,the even distribution of Treact – Tini is obtained irrespective of thickness of PEM,Tini and relative humidity conditions.Treact – Tini using Nafion 115 is higher than the other thin PEMs irrespective of Tini and relative humidity conditions.It can be concluded that the even temperature distribution could be achieved by using thin PEM and GDL.

猕猴桃不同品种需冷量的研究

以早鲜、金丰、素香、魁蜜等4个中华猕猴桃品种,米良1号、沪美1号、徐香、金魁等4个美味猕猴桃品种,共8个栽培品种为试材,取休眠枝于4℃处理不同时间后进行室内水培,利用0～7.2℃有效低温量评价模式测定需冷量。结果表明:8个品种中以早鲜需冷量最低,为552小时;金丰、素香、魁蜜、米良1号、沪美1号和徐香分别为600、696、744、744、792和888小时;金魁超过试验设定最大值(936小时)。美味猕猴桃的总体需冷量水平高于中华猕猴桃。原产地纬度在北纬30°以上的金魁、徐香和沪美1号需冷量较大;原产地纬度在北纬30°以下的早鲜、金丰、素香、魁蜜和米良1号需冷量较小。据此推测,需冷量可作为猕猴桃种群和生态群划分的依据之一。

设施葡萄22个常用品种需冷量的研究

利用0～7.2℃模型、≤7.2℃模型和犹它模型3种需冷量估算模型对设施葡萄常用品种的需冷量进行估算。结果表明,设施葡萄常用品种的需冷量值分布较广,若以0～7.2℃模型进行估算则介于573～971h之间,若以≤7.2℃模型进行估算则介于573～1246h之间,若以犹它模型进行估算则介于917～1090C?U之间;欧美种品种群品种需冷量值普遍高于欧亚种品种群品种;设施葡萄品种的需冷量值和其果实成熟期没有必然联系;3种需冷量估算模型估算设施葡萄品种的需冷量值差别较大。

Multi-Model Ensemble Projection of Precipitation Changes over China under Global Warming of 1.5 and 2℃ with Consideration of Model Performance and Independence

A weighting scheme jointly considering model performance and independence(PI-based weighting scheme) is employed to deal with multi-model ensemble prediction of precipitation over China from 17 global climate models. Four precipitation metrics on mean and extremes are used to evaluate the model performance and independence. The PIbased scheme is also compared with a rank-based weighting scheme and the simple arithmetic mean(AM) scheme. It is shown that the PI-based scheme achieves notable improvements in western China, with biases decreasing for all parameters. However, improvements are small and almost insignificant in eastern China. After calibration and validation, the scheme is used for future precipitation projection under the 1.5 and 2℃ global warming targets(above preindustrial level). There is a general tendency to wetness for most regions in China, especially in terms of extreme precipitation. The PI scheme shows larger inhomogeneity in spatial distribution. For the total precipitation PRCPTOT(95 th percentile extreme precipitation R95 P), the land fraction for a change larger than 10%(20%) is 22.8%(53.4%)in PI, while 13.3%(36.8%) in AM, under 2℃ global warming. Most noticeable increase exists in central and east parts of western China.

枸杞不同品种需冷量的研究

本文以我国枸杞主栽品种宁杞1号,以及枸杞新品种宁杞6号、宁杞8号和宁杞9号共四个枸杞品种为试材,做了不同枸杞品种需冷量的研究,为枸杞新品种的引种、推广提供了重要的理论依据。

Changes in Extreme Maximum Temperature Events and Population Exposure in China under Global Warming Scenarios of 1.5 and 2.0°C: Analysis Using the Regional Climate Model COSMO-CLM

We used daily maximum temperature data（1986–2100） from the COSMO-CLM（COnsortium for Small-scale MOdeling in CLimate Mode） regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events（EMTEs） with the intensity–area–duration method. Between 1986 and 2005（reference period）, the frequency, intensity, and coverage of EMTEs are 1330–1680 times yr^–1, 31.4–33.3℃, and 1.76–3.88 million km^2, respectively. The center of the most severe EMTEs is located in central China and 179.5–392.8 million people are exposed to EMTEs annually. Relative to 1986–2005, the frequency, intensity, and coverage of EMTEs increase by 1.13–6.84, 0.32–1.50, and15.98%–30.68%, respectively, under 1.5℃ warming; under 2.0℃ warming, the increases are 1.73–12.48, 0.64–2.76,and 31.96%–50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5℃ warming, one in North China and the other in Southwest China. Under 2.0℃ warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0℃ warming, population exposure is projected to increase by 23.2%–39.2% and 26.6%–48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0℃ warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0℃ will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5℃.

Uncertainty in the 2℃ Warming Threshold Related to Climate Sensitivity and Climate Feedback

Climate sensitivity is an important index that measures the relationship between the increase in greenhouse gases and the magnitude of global warming.Uncertainties in climate change projection and climate modeling are mostly related to the climate sensitivity.The climate sensitivities of coupled climate models determine the magnitudes of the projected global warming.In this paper,the authors thoroughly review the literature on climate sensitivity,and discuss issues related to climate feedback processes and the methods used in estimating the equilibrium climate sensitivity and transient climate response（TCR）,including the TCR to cumulative CO2 emissions.After presenting a summary of the sources that affect the uncertainty of climate sensitivity,the impact of climate sensitivity on climate change projection is discussed by addressing the uncertainties in 2℃ warming.Challenges that call for further investigation in the research community,in particular the Chinese community,are discussed.

Projection of weather potential for winter haze episodes in Beijing by 1.5℃ and 2.0℃ global warming

Haze episodes become very frequent in Beijing over the past decade,and such trend is related to favorable weather conditions.Here,we project the changes of weather conditions conducive to winter haze episodes in Beijing by 1.5℃ and 2.0℃ global warming using Haze Weather Index(HWI)and data of ensemble simulations from the Community Earth System Model(CESM)low-warming experiment.Compared to present day(2006–2015),the frequency in winter season is projected to increase by 14% for regular haze episodes(HWI>0)and 21% for severe haze episodes(HWI>1)at the 1.5℃ global warming.Projections shows larger increases of 27% for regular and 18%for severe haze events at the 2℃ global warming.The additional warming of 0.5℃ largely enhances the persistence of weather conditions conducive to haze episodes.The increased temperature contrast between near-surface and mid-troposphere in eastern Asia accounts for 57% and 81% of the change in HWI by 1.5℃ and 2℃ warming,respectively.Considering increased haze weather potential caused by climate warming,we suggest that additional efforts in emission reductions of carbon dioxide and air pollution are necessary to mitigate haze episodes in Beijing.

Distinct response of Northern Hemisphere land monsoon precipitation to transient and stablized warming scenarios

To better understand the climate response under stabilized,overshoot,and transient global warming,four types of ensemble experiments on 1.5℃/2℃ global warming scenarios(i.e.,stabilized 1.5℃,1.5℃ overshoot,stabilized 2℃,and transient 2℃)are elaborately designed using the Nanjing University Information Science and Technology Earth System Model(NESM).Compared with the modern climate(1985–2014),the projected surface air temperature(SAT)change is characterized by a robust‘Northern Hemisphere(NH)-warmer than-Southern Hemisphere(SH)’and‘land-warmer than-ocean’patterns.The projected precipitation change exhibits‘NH-wetter than-SH’pattern in the tropics.Although the response of SAT and precipitation climatology show similar pattern between stabilized and overshoot scenarios,some significant differences are still found.The projected change in the Northern Hemisphere land monsoon precipitation(NHLMP)is 30% larger in the transient 2℃ experiment compared with that in the stabilized 2℃ experiment.The more vigorous NHLMP in the transient global warming scenario is mainly due to the enhanced land-sea thermal contrast and interhemispheric temperature difference.The enlarged land-sea thermal contrast increases the surface pressure gradient between the NH continents and its adjacent oceans,thus enhancing the NH monsoon circulation and moisture convergence.The enhanced interhemispheric temperature difference shifts the Hadley circulation and intertropical convergence zone northward,leading to the enhanced moisture convergence and the shifts of tropical rain band over the NH monsoon region.This result highlights that climate responses may depend on different warming trajectories and,which could facilitate the strategic planning of governments.