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71.
赵美艳 《中国农学通报》2017,33(31):105-111
为了分析冬季热带太平洋中部海温升高对中国南方冬季降水的影响,本研究利用国际太平洋研究中心的区域气候模式(IPRC-RegCM)对2008年初南方典型的大范围雨雪天气过程进行数值模拟。结果表明:该模式能够较好的模拟出此次持续性降雨(雪)过程的雨带分布。且当在热带太平洋中部海域加入扰动热源后,中国南方大部分地区均以上升气流为主,南海地区水汽输送增强,有利于我国南方雨雪天气的发生。  相似文献   
72.
总结影响地面气象观测数据质量的四个主要因素分别为自然因素、设备因素、网络因素、人 为因素。针对地面气象观测数据异常提出相应的对策,说明想要提高地面气象观测数据的准确性,就 必须提高工作人员的专业素质、完善观测仪器设备的管理工作、加强测报运行监控预警系统等。  相似文献   
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74.
Frequent occurrences of extreme rainfall events create severe threat to agricultural production. This is one of the most significant consequences of global warming due to increase in greenhouse gases. A precise understanding of frequency and magnitude of these events and its influence on agricultural productivity can extensively help in policy decisions and planning agricultural as well as water management operations. This study has analyzed observed trends in extreme rainfall indices during monsoon months as well as seasonally at four stations located over different agro-ecological zones of Bihar, namely Samastipur (zone-I), Madhepura (zone-II), Sabour (zone-IIIA) and Patna (zone-IIIB). Mann-Kendall nonparametric test was employed for detection of trends and the slopes of the trend lines were determined using the method of least square linear fitting. Since rice is the important crop in this part of the region, the vulnerability of extreme rainfall indices on productivity also analysed using simple correlations. All the sites show an increasing trend of number of days with rainfall 10.0 cm or more (very heavy precipitation event) during monsoon season. Sabour shows a significant increasing trend of 0.4 and 0.6 day/decade, respectively during monsoon and annually. During September, occurrence of heavy precipitation events over Madhepura recorded a significant positive trend of 0.4 day/decade. Highly significant magnitudes of increasing trends were noticed for Madhepura (46.6 mm/decade) and Sabour (27.5 mm/decade) for occurrence of highest five-day total precipitation during monsoon season. The results show statistically significant positive trends of number of days with rainfall > R2.5 cm for all the study sites during August. All the sites, the magnitude of highest 1-day and 5-days maximum rainfall is showing increasing trend. Increasing trends of fraction of rainfall due to extremely wet days is also showing increasing trend in all the sites. The rice productivity showed 10th degree polynomial technological trend in all the sites and steady increase in all the sites except Samastipur. The correlation between extreme rainfall indices during monsoon season and productivity anomaly index indicate that almost all the extreme rainfall indices contribute positively to rice productivity except P95pTOT and R99pTOT over Sabour and R7.5 cm over Patna. If we assume the observed increasing trends in different extreme rainfall indices will continue, as estimated by the global circulation models, the chances of occurrence of intense rainfall events in near future will also increase proportionally and efforts should be made to prepare detailed site specific—at least at district level—disastrous management plan especially to reduce impact of extreme rainfall event on agricultural production system under changing climatic scenarios.  相似文献   
75.
Non-selective computed tomography angiography (CTA) is an emerging imaging technique that will have continued application in veterinary medicine because of its short scan time, use of a single, peripheral venous injection and availability of more detailed anatomic information—including 3-dimensional reconstructions. The improved anatomic detail may facilitate veterinary students' learning of complex aortic arch malformations and details relative to the surgical approach. Herein we describe application of its use in a dog with a vascular ring anomaly due to a persistent right fourth aortic arch and left ligamentum arteriosum. Additionally, we compare images with a normal dog.  相似文献   
76.
黑龙江省近50年日照时数变化特征分析   总被引:3,自引:0,他引:3  
为使黑龙江省气象资源更好地为农业服务,利用黑龙江省71个台站1961~2010年日照时数统计资料,采用线性倾向估计法与累计距平法分析黑龙江省日照时数的年、季和月变化特征.结果表明:近50年来黑龙江省年日照时数呈显著减少趋势,平均每10年减少26.7 h ;20世纪60年代年平均日照时数最多,90年代最少;年日照时数最多为1967年,最少为2003年;四季日照时数均呈减少趋势,春季最为明显,其次为冬季、夏季,秋季最不明显;除8月、9月外,各月日照时数均呈减少趋势,其中6月最为明显;日照时数变化趋势转折时间大致出现在20世纪80年代初期.  相似文献   
77.
近60年西南地区降水异常的气候特征分析   总被引:1,自引:0,他引:1  
张荣  庞晶  覃军 《安徽农业科学》2012,(30):14873-14875
[目的]分析1951~2010年西南地区降水气候异常的时空分布特征。[方法]利用1951~2010年西南地区44个站点和全国160个站点月降水资料,采用EOF分析、小波分析、合成分析等方法,对西南地区降水在月、季时间尺度的变化规律进行详尽的分析,且研究了旱、涝年对应的降水时空分布特征,全面揭示近60年西南地区降水气候异常的时空分布特征。[结果]西南地区降水的季节分配不均匀,为典型的单峰型,降水集中期为5~9月,峰值出现在7月;近年来秋季降水有明显变少的趋势,其他季节变化趋势不明显;该地区夏季降水的主要显著周期为14年,还存在6年以及3~4年周期振荡;涝年降水与华南地区呈同位相,与西部青、甘、新、藏交界处呈反位相,旱年与西北东部和华北地区降水呈同位相。[结论]该研究为该地区降水的预测预警提供参考依据。  相似文献   
78.
A hybrid surgical approach and balloon dilatation were performed successfully in a cat with cor triatriatum sinister and clinical signs of congestive heart failure. Left lateral thoracotomy was used to access the heart and cutting balloon followed by standard balloon dilatation were utilized to dilate the perforation in the anomalous left atrial membrane. Clinical signs resolved completely after dilation of the anomalous left atrial membrane. Based upon the outcome of this case, balloon dilatation appears to be a viable treatment option for cats affected with cor triatriatum sinister.  相似文献   
79.
A 3‐month wild rabbit was presented for examination of ocular opacities in the left eye. A complete bilateral ocular examination including slit‐lamp examination, indirect ophthalmoscopy, tonometry, and ultrasound biomicroscopy was performed. Biomicroscopy of the lens of the left eye showed a retrolental fibrovascular membrane causing leukocoria. The opacity prevented biomicroscopy of the vitreous and funduscopy OS. No other disorder was present in either eye. Ultrasound examination did not show any difference between the right and left eye. Histopathological examination showed a 50‐μm thick, preretinal, retrolental, nonpigmented, fibrovascular tissue. Posterior synechiae were present, but no other lesion of the posterior segment was found in this eye. These ocular abnormalities are consistent with a persistent hyperplastic tunica vasculosa lentis and persistent hyperplastic primary vitreous (PHTVL/PHPV), similar to those described in other species.  相似文献   
80.
Background: Portal vein thrombosis (PVT) in cats is sparsely reported.
Purpose of Study: To evaluate the clinical signs and diseases associated with PVT in cats.
Animals: 6 client-owned cats.
Methods: Medical records for cats with a portal vein thrombus diagnosed on abdominal ultrasound or at necropsy were reviewed. Signalment, historical data, underlying disorders, clinical findings, clinicopathologic and histopathologic data, diagnostic imaging findings, treatment, and outcome were recorded.
Results: All 6 cats identified with PVT also had hepatic disease. Evidence of a congenital portosystemic shunt was present in 3/6 cats. Two cats had primary or metastatic hepatic neoplasia. One cat had acute cholangitis, acute pancreatitis, and locally extensive acute centrilobular hepatic necrosis. Two cats were suspected to have acute thrombi and 4 cats had chronic thrombi.
Conclusion and Clinical Significance: PVT might be an important concurrent finding in cats with hepatic disease.  相似文献   
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