Changing Trend and Mutation Analysis of Number of Fog and Haze Days in Baoji City during 1981-2013

Based on data of number of fog and haze days in Baoji City from 1981 to 2013,the changing trends and mutation of number of fog and haze days in Baoji over the past 33 years were analyzed by using trend coefficient,tendency rate,linear regression analysis,anomaly percentage,Mann-Kendall mutation test and sliding t test.The results showed that during the 33 years,the number of fog and haze days in Baoji declined by 16.253d/10 a,and there was a cyclical turbulence every 6,15 or 28years.The frequency of fog and haze weather was the highest in winter,followed by spring and autumn,while it was the lowest in summer.According to the anomaly percentage of the number of fog and haze days in 12 months during 1981-2013,the anomaly percentage changed most greatly in July,followed by September,October,April,May,June,August,February and March,but it fluctuated less greatly in January.The number of fog and haze days from 1981 to 2013had obvious mutation trends in a single year and a single season,and mutation types are different.

Geophysical Features of the Ore-Controlling Fault in the Chang'an Gold Deposit, Southern Yunnan Province

The Ailao Mountain is one of the most important metallogenic belts ofpolymetallic deposits in the Sanjiang region, southwestern China. Located in the southern segment of this metallogenic belt, the newly-discovered Chang＇an gold deposit is large in scale （Fig. 1A）, and has attracted much attention among geologists. The ore-hosted rocks in the district include the Late Ordovician Xiangyang Fm. sandstone and clastic rocks and the Early Silurian Kanglang Fm. dolomite. Affected by the multistage tectonic activities, stocks and dykes of lamprophyre, dolerite, syenite porphyry and orthoclasite are widely exposed, and the orebodies are in symbiosis with or crosscut the dyke rocks.

Changes in the Features of Major Contradictions

Immediately after humanity entered the new century,the worldseems somewhat a bit turbulent because of the following events.First are the September 11 events,which were followed by U.S.militaryattacks against Afghanistan.Last year witnessed the continuity of Arab-Israel conflicts in the Middle East,and at the very beginning of the newyear,the United States dispatched warships to the Persian Gulf for a“war to topple the Saddam regime”.The Democratic People’s Republicof Korea(DPRK)suddenly declared that it has decided to withdraw fromthe Nuclear Non-proliferation Treaty just after Iraq stated that it wasdetermined to resist the United States.Whither the world in the new year?This is a question that all of the academic circles on international relationsare trying to answer.To this end,on January 9,2002,we speciallyinvited Lu Zhongwei,Research Professor and President of China Instituteof Contemporary International Relations and some other experts oninternational relations from the institute to hold a symposium with the theme“Prospect on World Trend 2003.”Now we present their discussions as anew-year gift to our readers who are always in support of our journal.Wehope this would do a bit for their mastery of international situation.

Temporal Variations in Sea of Clouds and Their Relation with Meteorological Factors in Yandang Mountains

Based on data of meteorological elements in the meteorological station in North Yandang Mountains during 1960- 2013,temporal variations in days of sea of clouds over Yandang Mountains in nearly 50 years and their relation with air temperature,precipitation,relative humidity and wind speed were analyzed. The results showed that annual average days of sea of clouds over Yandang Mountains were 164. 92 d,and the maximum and minimum were 215 and 58 d,so there was a big difference between various years. The days of sea of clouds were the most in spring,and average days of sea of clouds（ average days of sea of clouds with low cloud cover ≥80%） were 50. 89 d（ 32. 77 d）,while they were the least in autumn. There was an obvious positive correlation between the days of sea of clouds and relative humidity. Precipitation occurred the day before or on the day when sea of clouds with low cloud cover ≥80% formed. On the day when sea of clouds with low cloud cover ≥80% appeared,average relative humidity was ≥80%,and average wind speed was ≤4. 5 m/s.

ABRUPT CHANGE IN ELEMENTS AROUND 1998 SCS SUMMER MONSOON ESTABLISHMENT WITH ANALYSIS OF ITS CHARACTERISTIC PROCESS

The latest dataset from the SCS(South China Sea)Monsoon Experiment is used to investigate the features of abrupt change in some meteorological elements before,during and after the summer monsoon's establishment in 1998 and explore its onset characteristic process.We have arrived at a preliminary conclusion that the 1998 Asian summer monsoon is established first in the SCS as early as May 23,which is representative of the earliest indicator of the conversion from a winter into a summer monsoon situation in Asia;the continued retreat eastward of the western Pacific subtropical high from the SCS region has direct effect on the SCS summer monsoon establishment because the withdrawal favors the release of unstable energy,responsible for the sudden onset of the monsoon.Our tentative investigation indicates that the eastward extension of the westerly and rainfall band from the equatorial Indian Ocean into the Indo-China Peninsula and the southward spreading of an active South-China stationary front,acting as the interaction between mid and low latitude systems,are likely to be the characteristic events contributing to the subtropical high's eastward retreating and the summer monsoon's onset over the SCS.

Impacts of climate change on mangrove ecosystems:a region by region overview

Inter-related and spatially variable climate change factors including sea level rise,increased storminess,altered precipitation regime and increasing temperature are impacting mangroves at re-gional scales.This review highlights extreme regional variation in climate change threats and impacts,and how these factors impact the structure of mangrove communities,their biodiversity and geo-morphological setting.All these factors interplay to determine spatially variable resiliency to climate change impacts,and because mangroves are varied in type and geographical location,these systems are good models for understanding such interactions at different scales.Sea level rise is likely to in-fluence mangroves in all regions although local impacts are likely to be more varied.Changes in the frequency and intensity of storminess are likely to have a greater impact on N and Central America,Asia,Australia,and East Africa than West Africa and S.America.This review also highlights the nu-merous geographical knowledge gaps of climate change impacts,with some regions particularly understudied(e.g.,Africa and the Middle East).While there has been a recent drive to address these knowledge gaps especially in South America and Asia,further research is required to allow research-ers to tease apart the processes that influence both vulnerability and resilience to climate change.A more globally representative view of mangroves would allow us to better understand the importance of mangrove type and landscape setting in determining system resiliency to future climate change.

Future wet grasslands:ecological implications of climate change

Wet grasslands are threatened by future climate change,yet these are vital ecosystems for both conservation and agriculture,providing livelihoods for millions of people.These biologically diverse,transitional wetlands are defined by an abundance of grasses and periodic flooding,and maintained by regular disturbances such as grazing or cutting.This study summarizes relevant climate change scenarios projected by the Intergovernmental Panel on Climate Change and identifies implications for wet grasslands globally and regionally.Climate change is predicted to alter wet grassland hydrology,especially through warming,seasonal precipitation variability,and the severity of extreme events such as droughts and floods.Changes in the diversity,composition,and productivity of vegetation will affect functional and competitive relations between species.Extreme storm or flood events will favor ruderal plant species able to respond rapidly to environmental change.In some regions,wet grasslands may dry out during heatwaves and drought.C4 grasses and invasive species could benefit from warming scenarios,the latter facilitated by disturbances such as droughts,floods,and possibly wildfires.Agriculture will be affected as forage available for livestock will likely become less reliable,necessitating adaptations to cutting and grazing regimes by farmers and conservation managers,and possibly leading to land abandonment.It is recommended that agri-environment schemes,and other policies and practices,are adapted to mitigate climate change,with greater emphasis on water maintenance,flexible management,monitoring,and restoration of resilient wet grasslands.