The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in ...The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in precipitation in the southeastern edge of the plateau have resulted in cutting-edge research regarding the impact of the TP and its surrounding areas on downstream weather and climate.In this study,the spatial and temporal distribution of surface heat flux and precipitation were analyzed from 1998 to 2022,and the possible mechanism of the decrease of precipitation in the eastern edge of the plateau is explored.The main conclusions are as follows:The annual average sensible heat flux in the TP and its east side is positive,with an average of 33.73 W/m^(2).The annual average latent heat flux is positive,with an average of 42.71 W/m^(2).Precipitation has a similar annual average and seasonal distribution,with modest amounts in the northwest and substantial amounts in the southeast.The average annual accumulated precipitation is 670.69 mm.The first mode of the Empirical Orthogonal Function(EOF)shows that sensible heat flux decreases first,then increases,and then finally decreases during 1998–2022.The modes show the opposite trend in middle part of the plateau.The latent heat flux initially decreases,then increases,and finally decreases in the western plateau and near Sichuan Basin.The mode,however,displays the opposite tendency throughout the rest of the region.The precipitation in the north and south sides of the plateau has decreased since 2013,which is consistent with the changing trend of sensible heat flux.In the rest of the region,the change trend is not obvious.The sensible heat of the main body of the plateau and its east side and Sichuan Basin is negatively correlated with precipitation,that is,when sensible heat flux of the main body of the plateau and its east side and Sichuan Basin is more(less),local precipitation is less(more).The latent heat of the main body of the plateau and its east side,Sichuan Basin is positively correlated with precipitation,indicating that when latent heat flux of the main body of the plateau and its east side,Sichuan Basin is more(less),local precipitation is more(less).展开更多
The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of t...The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of the two slopes.In this paper,data from TESEBS(Topographical Enhanced Surface Energy Balance System),remote sensing data from eight cloud-free scenarios,and observational data from nine stations are utilized to examine the fluctuations in the surface heat flux on both slopes.The inclusion of MCD43A3 satellite data enhances the surface albedo,contributing to more accurate simulation outcomes.The model results are validated using observational data.The RMSEs of the net radiation,ground heat,sensible heat,and latent heat flux are 40.73,17.09,33.26,and 30.91 W m^(−2),respectively.The net radiation flux is greater on the south slope and exhibits a rapid decline from summer to autumn.Due to the influence of the monsoon,on the north slope,the maximum sensible heat flux occurs in the pre-monsoon period in summer and the maximum latent heat flux occurs during the monsoon.The south slope experiences the highest latent heat flux in summer.The dominant flux on the north slope is sensible heat,while it is latent heat on the south slope.The seasonal variations in the ground heat flux are more pronounced on the south slope than on the north slope.Except in summer,the ground heat flux on the north slope surpasses that on the south slope.展开更多
“Earth summit mission 2022”is one of the landmark scientific research activities of the Second Tibetan Plateau Scientific Expedition and Research(STEP).This scientific expedition firstly used advanced technology and...“Earth summit mission 2022”is one of the landmark scientific research activities of the Second Tibetan Plateau Scientific Expedition and Research(STEP).This scientific expedition firstly used advanced technology and methods to detect vertical meteorological elements and produce forecasts for mountain climbing.The“Earth summit mission 2022”Qomolangma scientific expedition exceeded an altitude of over 8000 meters for the first time and carried out a comprehensive scientific investigation mission on the summit of Mt.Qomolangma.Among the participants,the westerly–monsoon synergy and influence team stationed in the Mt.Qomolangma region had two tasks:1)detecting the vertical structure of the atmosphere for parameters such as wind,temperature,humidity,and pressure with advanced instruments for high-altitude detection at the Mt.Qomolangma base camp;and 2)observing extreme weather processes to ensure that members of the mountaineering team could successfully reach the top.Through this scientific expedition,a better understanding of the vertical structure and weather characteristics of the complex area of Mt.Qomolangma is gained.展开更多
An automatic weather station(AWS) has been installed at the Qomolangma Station of the China Academy of Sciences(QOMS) since 2005, in a northern Himalayan valley near Mount Everest, with an altitude of 4,270 m a.s.l.. ...An automatic weather station(AWS) has been installed at the Qomolangma Station of the China Academy of Sciences(QOMS) since 2005, in a northern Himalayan valley near Mount Everest, with an altitude of 4,270 m a.s.l.. Nine years of meteorological records(2006–2014) from the automatic weather station(AWS) were analyzed in this study, aiming to understand the response of local weather to the seasonal transition on the northern slopes of Mount Everest, with consideration of the movement of the subtropical jet(STJ) and the onset of the Indian Summer Monsoon(ISM). We found:(1) Both the synoptic circulation and the orography have a profound influence on the local weather, especially the local circulation.(2) Southwesterly(SW) and southeasterly(SE) winds prevail alternately at QOMS in the afternoon through the year. The SW wind was driven by the STJ during the non-monsoon months, while the SE was induced by the trans-Himalayan flow through the Arun Valley, a major valley to the east of Mount Everest, under a background of weak westerly winds aloft.(3) The response of air temperature(T) and specific humidity(q) to the monsoon onset is not as marked as that of the nearsurface winds. The q increases gradually and reaches a maximum in July when the rainy period begins.(4) The alternation between the SW wind at QOMS and the afternoon SE wind in the pre-monsoon season signals the northward shift of the STJ and imminent monsoon onset. The average interval between these two events is 14 days.展开更多
Histone H3 lysine 4 trimethylation （H3K4me3） is well known to occur in the promoter region of genes for transcription activation. How- ever, when investigating the H3K4me3 profiles in the mouse cerebrum and testis, ...Histone H3 lysine 4 trimethylation （H3K4me3） is well known to occur in the promoter region of genes for transcription activation. How- ever, when investigating the H3K4me3 profiles in the mouse cerebrum and testis, we discovered that H3K4me3 also has a significant enrichment at the 3＇ end of actively transcribed （sense） genes, named as 3＇-H3K4me3. 3＇-H3K4me3 is associated with ~15% of pro- tein-coding genes in both tissues. In addition, we examined the transcriptional initiation signals including RNA polymerase II （RNAPII） binding sites and Y-CAGE-tag that marks transcriptional start sites. Interestingly, we found that 3＇-H3K4me3 is associated with the ini- tiation of antisense transcription. Furthermore, 3＇-H3K4me3 modification levels correlate positively with the antisense expression levels of the associated sense genes, implying that 3＇-H3K4me3 is involved in the activation of antisense transcription. Taken together, our findings suggest that H3K4me3 may be involved in the regulation of antisense transcription that initiates from the 3＇ end of sense genes. In addition, a positive correlation was also observed between the expression of antisense and the associated sense genes with 3＇-H3K4me3 modification. More importantly, we observed the 3＇-H3K4me3 enrichment among genes in human, fruitfly and Arabidopsis, and found that the sequences of 3＇-H3K4me3-marked regions are highly conserved and essentially indistinguishable from known promoters in ver- tebrate. Therefore, we speculate that these 3＇-H3K4me3-marked regions may serve as potential promoters for antisense transcription and 3＇-H3K4me3 appear to be a universal epigenetic feature in eukaryotes. Our results provide a novel insight into the epigenetic roles of H3K4me3 and the regulatory mechanism of antisense transcription.展开更多
The global features of H3K4 and H3K27 trimethylations （H3K4me3 and H3K27me3） have been well studied in recent years, but most of these studies were performed in mammalian cell lines. In this work, we generated the g...The global features of H3K4 and H3K27 trimethylations （H3K4me3 and H3K27me3） have been well studied in recent years, but most of these studies were performed in mammalian cell lines. In this work, we generated the genorne-wide maps of H3K4me3 and H3K27me3 of mouse cerebrum and testis using ChlP-seq and their high-coverage transcriptomes using ribominus RNA-seq with SOLID technology. We examined the global patterns of H3K4me3 and H3K27me3 in both tissues and found that modifications are closely-associated with tissue-specific expression, function and development. Moreover, we revealed that H3K4me3 and H3K27me3 rarely occur in silent genes, which contradicts the findings in previous studies. Finally, we observed that bivalent domains, with both H3K4me3 and H3K27me3, existed ubiquitously in both tissues and demonstrated an invariable preference for the regulation of developmentally-related genes. How- ever, the bivalent domains tend towards a ＂winner-takes-all＂ approach to regulate the expression of associated genes. We also verified the above results in mouse ES cells. As expected, the results in ES cells are consistent with those in cerebrum and testis. In conclusion, we present two very important findings. One is that H3K4me3 and H3K27me3 rarely occur in silent genes. The other is that bivalent domains may adopt a ＂winner-takes-all＂ principle to regulate gene expression.展开更多
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0103)the National Natural Science Foundation of China(Grant No.42230610)+2 种基金the Natural Science Foundation of Sichuan Province(Grant No.2022NSFSC0217)National key research and development program of China(2017YFC1505702)Scientific Research Project of Chengdu University of Information Technology(KYTZ201721).
文摘The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in precipitation in the southeastern edge of the plateau have resulted in cutting-edge research regarding the impact of the TP and its surrounding areas on downstream weather and climate.In this study,the spatial and temporal distribution of surface heat flux and precipitation were analyzed from 1998 to 2022,and the possible mechanism of the decrease of precipitation in the eastern edge of the plateau is explored.The main conclusions are as follows:The annual average sensible heat flux in the TP and its east side is positive,with an average of 33.73 W/m^(2).The annual average latent heat flux is positive,with an average of 42.71 W/m^(2).Precipitation has a similar annual average and seasonal distribution,with modest amounts in the northwest and substantial amounts in the southeast.The average annual accumulated precipitation is 670.69 mm.The first mode of the Empirical Orthogonal Function(EOF)shows that sensible heat flux decreases first,then increases,and then finally decreases during 1998–2022.The modes show the opposite trend in middle part of the plateau.The latent heat flux initially decreases,then increases,and finally decreases in the western plateau and near Sichuan Basin.The mode,however,displays the opposite tendency throughout the rest of the region.The precipitation in the north and south sides of the plateau has decreased since 2013,which is consistent with the changing trend of sensible heat flux.In the rest of the region,the change trend is not obvious.The sensible heat of the main body of the plateau and its east side and Sichuan Basin is negatively correlated with precipitation,that is,when sensible heat flux of the main body of the plateau and its east side and Sichuan Basin is more(less),local precipitation is less(more).The latent heat of the main body of the plateau and its east side,Sichuan Basin is positively correlated with precipitation,indicating that when latent heat flux of the main body of the plateau and its east side,Sichuan Basin is more(less),local precipitation is more(less).
基金financially supported by the National Natural Science Foundation of China[grant number 42230610]the Second Tibetan Plateau Scientific Expedition and Research(STEP)program[grant number 2019QZKK0103]+1 种基金the Natural Science Foundation of Sichuan Province[grant number 2022NSFSC0217]the Scientific Research Project of Chengdu University of Information Technology[grant number KYTZ201721].
文摘The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of the two slopes.In this paper,data from TESEBS(Topographical Enhanced Surface Energy Balance System),remote sensing data from eight cloud-free scenarios,and observational data from nine stations are utilized to examine the fluctuations in the surface heat flux on both slopes.The inclusion of MCD43A3 satellite data enhances the surface albedo,contributing to more accurate simulation outcomes.The model results are validated using observational data.The RMSEs of the net radiation,ground heat,sensible heat,and latent heat flux are 40.73,17.09,33.26,and 30.91 W m^(−2),respectively.The net radiation flux is greater on the south slope and exhibits a rapid decline from summer to autumn.Due to the influence of the monsoon,on the north slope,the maximum sensible heat flux occurs in the pre-monsoon period in summer and the maximum latent heat flux occurs during the monsoon.The south slope experiences the highest latent heat flux in summer.The dominant flux on the north slope is sensible heat,while it is latent heat on the south slope.The seasonal variations in the ground heat flux are more pronounced on the south slope than on the north slope.Except in summer,the ground heat flux on the north slope surpasses that on the south slope.
基金funded by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0103)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20060101)the National Natural Science Foundation of China(Grant Nos.91837208,41830650).
文摘“Earth summit mission 2022”is one of the landmark scientific research activities of the Second Tibetan Plateau Scientific Expedition and Research(STEP).This scientific expedition firstly used advanced technology and methods to detect vertical meteorological elements and produce forecasts for mountain climbing.The“Earth summit mission 2022”Qomolangma scientific expedition exceeded an altitude of over 8000 meters for the first time and carried out a comprehensive scientific investigation mission on the summit of Mt.Qomolangma.Among the participants,the westerly–monsoon synergy and influence team stationed in the Mt.Qomolangma region had two tasks:1)detecting the vertical structure of the atmosphere for parameters such as wind,temperature,humidity,and pressure with advanced instruments for high-altitude detection at the Mt.Qomolangma base camp;and 2)observing extreme weather processes to ensure that members of the mountaineering team could successfully reach the top.Through this scientific expedition,a better understanding of the vertical structure and weather characteristics of the complex area of Mt.Qomolangma is gained.
基金funded by the National Natural Science Foundation of China (41661144043, 41005010, 41475010)the Strategic Priority Research Program (A) of the Chinese Academy of Sciences (Grant XDA20060101)R & D Special Fund for Public Welfare Industry (meteorology), No. GYHY201406001
文摘An automatic weather station(AWS) has been installed at the Qomolangma Station of the China Academy of Sciences(QOMS) since 2005, in a northern Himalayan valley near Mount Everest, with an altitude of 4,270 m a.s.l.. Nine years of meteorological records(2006–2014) from the automatic weather station(AWS) were analyzed in this study, aiming to understand the response of local weather to the seasonal transition on the northern slopes of Mount Everest, with consideration of the movement of the subtropical jet(STJ) and the onset of the Indian Summer Monsoon(ISM). We found:(1) Both the synoptic circulation and the orography have a profound influence on the local weather, especially the local circulation.(2) Southwesterly(SW) and southeasterly(SE) winds prevail alternately at QOMS in the afternoon through the year. The SW wind was driven by the STJ during the non-monsoon months, while the SE was induced by the trans-Himalayan flow through the Arun Valley, a major valley to the east of Mount Everest, under a background of weak westerly winds aloft.(3) The response of air temperature(T) and specific humidity(q) to the monsoon onset is not as marked as that of the nearsurface winds. The q increases gradually and reaches a maximum in July when the rainy period begins.(4) The alternation between the SW wind at QOMS and the afternoon SE wind in the pre-monsoon season signals the northward shift of the STJ and imminent monsoon onset. The average interval between these two events is 14 days.
基金supported by Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No.KSCX2-EW-R-01-04)Natural Science Foundation of China (Grant No. 90919024 and 30900831)the National Basic Research Program (973 Program) from the Ministry of Science and Technology of China (GrantNo. 2011CB944100)
文摘Histone H3 lysine 4 trimethylation （H3K4me3） is well known to occur in the promoter region of genes for transcription activation. How- ever, when investigating the H3K4me3 profiles in the mouse cerebrum and testis, we discovered that H3K4me3 also has a significant enrichment at the 3＇ end of actively transcribed （sense） genes, named as 3＇-H3K4me3. 3＇-H3K4me3 is associated with ~15% of pro- tein-coding genes in both tissues. In addition, we examined the transcriptional initiation signals including RNA polymerase II （RNAPII） binding sites and Y-CAGE-tag that marks transcriptional start sites. Interestingly, we found that 3＇-H3K4me3 is associated with the ini- tiation of antisense transcription. Furthermore, 3＇-H3K4me3 modification levels correlate positively with the antisense expression levels of the associated sense genes, implying that 3＇-H3K4me3 is involved in the activation of antisense transcription. Taken together, our findings suggest that H3K4me3 may be involved in the regulation of antisense transcription that initiates from the 3＇ end of sense genes. In addition, a positive correlation was also observed between the expression of antisense and the associated sense genes with 3＇-H3K4me3 modification. More importantly, we observed the 3＇-H3K4me3 enrichment among genes in human, fruitfly and Arabidopsis, and found that the sequences of 3＇-H3K4me3-marked regions are highly conserved and essentially indistinguishable from known promoters in ver- tebrate. Therefore, we speculate that these 3＇-H3K4me3-marked regions may serve as potential promoters for antisense transcription and 3＇-H3K4me3 appear to be a universal epigenetic feature in eukaryotes. Our results provide a novel insight into the epigenetic roles of H3K4me3 and the regulatory mechanism of antisense transcription.
基金supported by Grants from Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-EW-R-01-04)National Science and Technology Key Project (2008ZX1004-013)+3 种基金863 Program(2009AA01A130)Special Foundation Work Program(2009FY120100)National Key Technology R&D Program (2008BA164B02)973 Program (2011CB944100,2011CB965300 and 2007CB948101) from the Ministry of Science and Technology of the People’s Republic of China
文摘The global features of H3K4 and H3K27 trimethylations （H3K4me3 and H3K27me3） have been well studied in recent years, but most of these studies were performed in mammalian cell lines. In this work, we generated the genorne-wide maps of H3K4me3 and H3K27me3 of mouse cerebrum and testis using ChlP-seq and their high-coverage transcriptomes using ribominus RNA-seq with SOLID technology. We examined the global patterns of H3K4me3 and H3K27me3 in both tissues and found that modifications are closely-associated with tissue-specific expression, function and development. Moreover, we revealed that H3K4me3 and H3K27me3 rarely occur in silent genes, which contradicts the findings in previous studies. Finally, we observed that bivalent domains, with both H3K4me3 and H3K27me3, existed ubiquitously in both tissues and demonstrated an invariable preference for the regulation of developmentally-related genes. How- ever, the bivalent domains tend towards a ＂winner-takes-all＂ approach to regulate the expression of associated genes. We also verified the above results in mouse ES cells. As expected, the results in ES cells are consistent with those in cerebrum and testis. In conclusion, we present two very important findings. One is that H3K4me3 and H3K27me3 rarely occur in silent genes. The other is that bivalent domains may adopt a ＂winner-takes-all＂ principle to regulate gene expression.
