scholarly journals Nonhomogeneous poisson process model of summer high temperature extremes over China

2022 ◽  
Author(s):  
Meng Gao ◽  
Han Zhang ◽  
Aidi Zhang ◽  
Yueqi Wang
Keyword(s):  
High Temperature ◽  
Poisson Process ◽  
Process Model ◽  
Nonhomogeneous Poisson Process ◽  
Temperature Extremes ◽  
High Temperature Extremes

scholarly journals Nonhomogeneous Poisson Process Model of Summer High Temperature Extremes Over China

2021 ◽  
Author(s):  
Meng Gao ◽  
Han Zhang ◽  
Aidi Zhang ◽  
Yueqi Wang
Keyword(s):  
High Temperature ◽  
Poisson Process ◽  
Poisson Regression ◽  
Process Model ◽  
Value Theory ◽  
Nonhomogeneous Poisson Process ◽  
Occurrence Rate ◽  
Temperature Extremes ◽  
Teleconnection Patterns ◽  
High Temperature Extremes

Abstract In this study, nonhomogeneous Poisson process (NHPP) models arising from the extreme value theory have been fitted to summer high temperature extremes (HTEs) at 359 meteorological stations over China. The seasonality and six prominent atmospheric teleconnection patterns in Northern Hemisphere are incorporated in the NHPP models reflecting the non-stationarity in occurrence rate in Poisson process of HTEs. In addition, Poisson regression model has also been applied to link HTEs and teleconnection patterns. The linkages of HTEs and teleconnection patterns have been identified in both NHPP modeling and Poisson regression. Composite maps of differences of 500-hPa geopotential height and wind fields in the positive and negative phases of teleconnection patterns are constructed to show the impacts of atmospheric circulation patterns on extreme heat events. The spatial pattern of the associated anticyclonic or cyclonic circulations with teleconnection patterns partly explains the spatial variability of the occurrences of summer HTEs over China.

scholarly journals Bayesian modeling and prediction of accrual in multi-regional clinical trials

2014 ◽  
Vol 26 (2) ◽  
pp. 752-765 ◽  
Author(s):  
Yi Deng ◽  
Xiaoxi Zhang ◽  
Qi Long
Keyword(s):  
Clinical Trials ◽  
Poisson Process ◽  
Process Model ◽  
Nonhomogeneous Poisson Process ◽  
Modeling And Prediction ◽  
Accuracy And Precision ◽  
Start Up ◽  
Accrual Rate ◽  
Model Region ◽  
Over Time

In multi-regional trials, the underlying overall and region-specific accrual rates often do not hold constant over time and different regions could have different start-up times, which combined with initial jump in accrual within each region often leads to a discontinuous overall accrual rate, and these issues associated with multi-regional trials have not been adequately investigated. In this paper, we clarify the implication of the multi-regional nature on modeling and prediction of accrual in clinical trials and investigate a Bayesian approach for accrual modeling and prediction, which models region-specific accrual using a nonhomogeneous Poisson process and allows the underlying Poisson rate in each region to vary over time. The proposed approach can accommodate staggered start-up times and different initial accrual rates across regions/centers. Our numerical studies show that the proposed method improves accuracy and precision of accrual prediction compared to existing methods including the nonhomogeneous Poisson process model that does not model region-specific accrual.

Future high-temperature extremes and stationarity

2018 ◽  
Vol 98 (3) ◽  
pp. 1115-1134 ◽  
Author(s):  
S. Parey ◽  
T. T. H. Hoang ◽  
D. Dacunha-Castelle
Keyword(s):  
High Temperature ◽  
Temperature Extremes ◽  
High Temperature Extremes

scholarly journals Summer High Temperature Extremes over China Linked to the Pacific Meridional Mode

2020 ◽  
Vol 33 (14) ◽  
pp. 5905-5917
Author(s):  
Ming Luo ◽  
Ngar-Cheung Lau ◽  
Wei Zhang ◽  
Qiang Zhang ◽  
Zhen Liu
Keyword(s):  
High Temperature ◽  
Land Surface ◽  
Southern China ◽  
Eastern China ◽  
Northern China ◽  
Temperature Extremes ◽  
The Pacific ◽  
Meridional Mode ◽  
High Temperature Extremes ◽  
Pacific Meridional Mode

AbstractThis study investigates the association between summer high temperature extremes (HTEs) over China and the Pacific meridional mode (PMM) that is characterized by an anomalous north–south sea surface temperature gradient and an anomalous surface circulation over the northeastern subtropical Pacific. It is found that the HTE activities over most parts of southern China (particularly eastern China) are prominently intensified during the positive PMM phase and weakened during the negative phase. Further examinations suggest that the PMM is linked with HTEs in China through processes that entail both eastward and westward development of signals emanating from the PMM site. The westward development is associated with the formation of an anomalous low-level cyclone over the western North Pacific (WNP), which may be viewed as a Matsuno–Gill-type response to the off-equatorial heating in the eastern Pacific. This circulation change is accompanied by anomalous ascent over WNP and northern China, and subsidence over eastern China. On the other hand, the eastward development process is linked to the PMM-induced displacement of the East Asian jet stream and the generation of a midlatitude Rossby wave train. In the positive PMM phase, the above circulation changes are accompanied by anomalous air subsidence and enhanced adiabatic heating, reduced precipitation, anomalous lower-level anticyclone, and rising surface pressure over the eastern part of China. Moreover, the land surface of that region receives more solar radiation. Opposite changes are discernible over northern China. These changes are favorable for the occurrence and persistence of HTEs over eastern China and tend to suppress HTEs over northern China.

scholarly journals Climate Characteristics of High-Temperature and Muggy Days in the Beijing-Tianjin-Hebei Region in the Recent 30 Years

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Guohua Zhang ◽  
Jian Guan ◽  
Jingyi Ai ◽  
Jiangtao Zhang ◽  
Xiaoqing Jin
Keyword(s):  
High Temperature ◽  
Precipitation Amount ◽  
The Other ◽  
Annual Precipitation ◽  
Temperature Extremes ◽  
The Past ◽  
Annual Precipitation Amount ◽  
High Temperature Extremes

The climate characteristics of high-temperature (37°C and above) and muggy days in the Beijing-Tianjin-Hebei region over the past 30 years from 1981 to 2010 are analyzed. The results are summarized as follows. During this period, the years with the most number of high-temperature days are 1997–2005 and 2009 in the Beijing-Tianjin-Hebei region, while high-temperature extremes appear in 1999, 2000, 2002, 2009, and 2010. This disparity between the years with high-temperature extremes and the years with the most number of high-temperature days is located primarily in the central and southern cities of the Beijing-Tianjin-Hebei region. High-temperature extremes in the southern cities appear in June and July, while high-temperature extremes in the other cities appear in July. The years with the most number of muggy days are 1994, 1997, 1998, 2000, and 2010 in the Beijing-Tianjin-Hebei region, but the years with the extreme muggy conditions appear in 1981, 2002, 2005, and 2010. The most number of muggy days are in July, and the muggy days in July and August account for about 90% of the entire summer. Over the 30-year period, no apparent changes are observed in the number of days with precipitation and the annual precipitation amount.

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