The 1998 summer-time floods at the Yangtze River basin of China, the severest in last 50 years or so, directly resulted from the abnormal extension of Meiyu (rainy season), which was related to a weak East Asian summe...The 1998 summer-time floods at the Yangtze River basin of China, the severest in last 50 years or so, directly resulted from the abnormal extension of Meiyu (rainy season), which was related to a weak East Asian summer monsoon and persistent anomalies of extratropical circulation. The long persistence of blocking over the Ural Mountains is a conspicuous feature. The physical processes responsible for the prolonged maintenance of this key system are investigated in terms of internal forcing (transient eddy upon basic flow) and external forcing (tropical heating forcing) via diagnosis and numerical experiments in the paper. Using the adjoint method, the location and structure of optimal perturbations favorable for the development and maintenance of Ural blocking are identified, which shows an apparent coincidence with the observed storm track at the eastern Atlantic to Europe sector. The diagnosis of E-vector and the response of baroclinic stationary wave to transient forcing both suggest further that the enhanced transient eddy activity favors the occurrence and maintenance of positive anomalies. The upper-level jet and heat sources (sinks) during that period are calculated, and the results indicate that the anomaly of upper jet and tropical heating is evident. The ensemble forecasting experiments by a GCM, IAP T42L9 show that the anomalous heating over the tropics, especially over the central-western Pacific and Atlantic, favors the formation of positive anomalies of height at the Ural region. Finally, a self-sustain mechanism of positive anomalies through two-way interaction between planetary stationary wave and transient eddy under the stimulation of anomalous tropical heating is proposed.展开更多
An igneous intrusion of 94m thick was discovered intruding into the Silurian sandstone from Tazhong 18 Well.The petroleum previously preserved in the Silurian sandstone reservoir was altered into black carbonaceous bi...An igneous intrusion of 94m thick was discovered intruding into the Silurian sandstone from Tazhong 18 Well.The petroleum previously preserved in the Silurian sandstone reservoir was altered into black carbonaceous bitumen by abnormally high heat stress induced by the igneous intrusion.The reflec-tance of the carbonaceous bitumen reaches as high as 3.54%,indicating that the bitumen had evolved into a high thermal evolution level.Similar to the Silurian samples from the neighboring Tazhong 11,Tazhong 12,Tazhong 45 and Tazhong 47 wells,the distribution of C27,C28 and C29 steranes of the car-bonaceous bitumen is still"V"-shaped and can still be employed as an efficient parameter in oil source correlation.The"V"-shaped distribution indicates that the hydrocarbons from the Tazhong 18 and the neighboring wells were all generated from the Middle-Upper Ordovician hydrocarbon source rocks.However,the oil source correlation parameters associated with and terpanes had been changed greatly by the high heat stress and can no longer be used in oil source correlation.Theδ13C values of the pe-troleum from the neighboring wells are between-32.53‰and-33.37‰,coincident with those of the Paleozoic marine petroleum in the Tarim Basin.However,theδ13C values of the carbonaceous bitumen from the Tazhong 18 Well are between-27.18‰and-29.26‰,isotopically much heavier than the pe-troleum from the neighboring wells.The content of light hydrocarbons(nC14-nC20)of the saturated hydrocarbon fraction in the carbonaceous bitumen is extremely higher than the content of heavy hy-drocarbons.The light/heavy hydrocarbon ratios(ΣnC21-/ΣnC22+)are between 4.56 and 39.17.In the saturated fraction,the even numbered hydrocarbons are predominant to the odd numbered,and the OEP(Odd to Even Predominance)values are between 0.22 and 0.49.However,the content of light hy-drocarbons in the petroleum from the neighboring wells is relatively low and the content of the even numbered hydrocarbons is almost equal to that of the odd numbered.Compared with the samples from the neighboring wells,the abundance of non-alkylated aromatic hydrocarbons,such as phenanthrenes,and polycyclic aromatic hydrocarbons(PAHs),such as fluoranthane,pyrene,benzo[a]anthracene and benzofluoranthene,are relatively high.展开更多
The area change of heat abnormity is not in accordance with conclusions of former thermal infrared remote sensing studies of the Qinghai-Tibet Plateau,which were that the temperature of Yarlung Zangbo River suture bel...The area change of heat abnormity is not in accordance with conclusions of former thermal infrared remote sensing studies of the Qinghai-Tibet Plateau,which were that the temperature of Yarlung Zangbo River suture belt of the southern Plateau is high and the northern temperature is low.The study result in this paper shows that the highest temperature is found in the Bangong Co-Nujiang River suture belt,the Yarlung Zangbo River suture belt temperature is the second highest,and the northern Tibet temperature is the lowest.The study demonstration area was the suture belt areas of the Yarlung Zangbo River and the Bangong Co-Nujiang River in the Qinghai-Tibet Plateau,where the land temperature of the Qinghai-Tibet Plateau and the bore temperature of field land surface were measured and the emissivity of land surface was calculated.In addition,the authors explore the mechanism of the relationship between thermal infrared remote sensing and constructing thermodynamics and reach four new conclusions about the thermodynamics of the Tibet Plateau.展开更多
基金the CAS Key project KZCX2-203 the Research Program for the Excellent State Key Laboratory! (Grant No.49823002)the Study on F
文摘The 1998 summer-time floods at the Yangtze River basin of China, the severest in last 50 years or so, directly resulted from the abnormal extension of Meiyu (rainy season), which was related to a weak East Asian summer monsoon and persistent anomalies of extratropical circulation. The long persistence of blocking over the Ural Mountains is a conspicuous feature. The physical processes responsible for the prolonged maintenance of this key system are investigated in terms of internal forcing (transient eddy upon basic flow) and external forcing (tropical heating forcing) via diagnosis and numerical experiments in the paper. Using the adjoint method, the location and structure of optimal perturbations favorable for the development and maintenance of Ural blocking are identified, which shows an apparent coincidence with the observed storm track at the eastern Atlantic to Europe sector. The diagnosis of E-vector and the response of baroclinic stationary wave to transient forcing both suggest further that the enhanced transient eddy activity favors the occurrence and maintenance of positive anomalies. The upper-level jet and heat sources (sinks) during that period are calculated, and the results indicate that the anomaly of upper jet and tropical heating is evident. The ensemble forecasting experiments by a GCM, IAP T42L9 show that the anomalous heating over the tropics, especially over the central-western Pacific and Atlantic, favors the formation of positive anomalies of height at the Ural region. Finally, a self-sustain mechanism of positive anomalies through two-way interaction between planetary stationary wave and transient eddy under the stimulation of anomalous tropical heating is proposed.
基金the National Key Basic Research and Development Project(Grant No.2005CB422103)
文摘An igneous intrusion of 94m thick was discovered intruding into the Silurian sandstone from Tazhong 18 Well.The petroleum previously preserved in the Silurian sandstone reservoir was altered into black carbonaceous bitumen by abnormally high heat stress induced by the igneous intrusion.The reflec-tance of the carbonaceous bitumen reaches as high as 3.54%,indicating that the bitumen had evolved into a high thermal evolution level.Similar to the Silurian samples from the neighboring Tazhong 11,Tazhong 12,Tazhong 45 and Tazhong 47 wells,the distribution of C27,C28 and C29 steranes of the car-bonaceous bitumen is still"V"-shaped and can still be employed as an efficient parameter in oil source correlation.The"V"-shaped distribution indicates that the hydrocarbons from the Tazhong 18 and the neighboring wells were all generated from the Middle-Upper Ordovician hydrocarbon source rocks.However,the oil source correlation parameters associated with and terpanes had been changed greatly by the high heat stress and can no longer be used in oil source correlation.Theδ13C values of the pe-troleum from the neighboring wells are between-32.53‰and-33.37‰,coincident with those of the Paleozoic marine petroleum in the Tarim Basin.However,theδ13C values of the carbonaceous bitumen from the Tazhong 18 Well are between-27.18‰and-29.26‰,isotopically much heavier than the pe-troleum from the neighboring wells.The content of light hydrocarbons(nC14-nC20)of the saturated hydrocarbon fraction in the carbonaceous bitumen is extremely higher than the content of heavy hy-drocarbons.The light/heavy hydrocarbon ratios(ΣnC21-/ΣnC22+)are between 4.56 and 39.17.In the saturated fraction,the even numbered hydrocarbons are predominant to the odd numbered,and the OEP(Odd to Even Predominance)values are between 0.22 and 0.49.However,the content of light hy-drocarbons in the petroleum from the neighboring wells is relatively low and the content of the even numbered hydrocarbons is almost equal to that of the odd numbered.Compared with the samples from the neighboring wells,the abundance of non-alkylated aromatic hydrocarbons,such as phenanthrenes,and polycyclic aromatic hydrocarbons(PAHs),such as fluoranthane,pyrene,benzo[a]anthracene and benzofluoranthene,are relatively high.
基金supported by the Knowledge Innovation Project of the Chi-nese Academy of Sciences(Grant No.CX000018).
文摘The area change of heat abnormity is not in accordance with conclusions of former thermal infrared remote sensing studies of the Qinghai-Tibet Plateau,which were that the temperature of Yarlung Zangbo River suture belt of the southern Plateau is high and the northern temperature is low.The study result in this paper shows that the highest temperature is found in the Bangong Co-Nujiang River suture belt,the Yarlung Zangbo River suture belt temperature is the second highest,and the northern Tibet temperature is the lowest.The study demonstration area was the suture belt areas of the Yarlung Zangbo River and the Bangong Co-Nujiang River in the Qinghai-Tibet Plateau,where the land temperature of the Qinghai-Tibet Plateau and the bore temperature of field land surface were measured and the emissivity of land surface was calculated.In addition,the authors explore the mechanism of the relationship between thermal infrared remote sensing and constructing thermodynamics and reach four new conclusions about the thermodynamics of the Tibet Plateau.
