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Li Y.,Lanzhou University | Ye P.,Lanzhou Central Meteorological Observatory | Pu Z.,University of Utah | Feng J.,Beijing Normal University | And 3 more authors.
Theoretical and Applied Climatology | Year: 2017

Using NCEP/NCAR reanalysis (NNR) data and 13 models from phase 5 of Coupled Model Intercomparison Project (CMIP5), this study focuses on historical statistics and future change in blocking over key regions (Urals, Baikal, and Okhotsk regions) in Eurasia. The statistical characteristic using NNR data shows that short-duration and long-duration blocking highs are 75 and 25% of the total, respectively. It is also shown that frequency of blocking highs presents a decreased trend in Eurasia during 1956–2006, except blocking highs in summer in Baikal region, long-duration blocking highs in summer, and short-duration blocking highs in winter in Okhotsk region. Compared with NNR, the frequency of blocking highs is underestimated in Eurasia by CMIP5 models, except these with long-duration in the Baikal and Okhotsk regions. Most of the CMIP5 models can reproduce the historical trend of blocking highs over Eurasia during 1956–2005. In addition, projections show that the future change of long-duration blocking highs in Eurasia is not always consistent with that in the whole Northern Hemisphere. The results of the multiple models ensemble (MME) suggest that long-duration blocking highs in the Urals will significantly increase by 0.3 times/10 years (decrease by 0.22 times/10 years) under RCP4.5 (RCP8.5) in the wintertime. In the summertime, the frequency fluctuates with little change. In Okhotsk, long-duration blocking highs will increase by 0.23 times/10 years (decrease by 0.22 times/10 years) in the wintertime (summertime) under RCP4.5. Under RCP8.5, long-duration blocking high frequency will remain the same, and the decreasing trend in the wintertime and the increasing trend (0.32 times/10 years) in the summertime will even accelerate over the trends in the twentieth century. © 2017 Springer-Verlag Wien


Wang C.,Nanjing University of Information Science and Technology | Wang C.,Lanzhou Institute of Arid Meteorology | Zhang S.,Lanzhou Institute of Arid Meteorology | Tian Y.,Nanjing University of Information Science and Technology | And 2 more authors.
International Journal of Environmental Research and Public Health | Year: 2014

The effects of simulated heat waves on body weight, body temperature, and biomarkers of cardiac function in ApoE-/- mice were investigated. Heat waves were simulated in a meteorological environment simulation chamber according to data from a heat wave that occurred in July 2001 in Nanjing, China. Eighteen ApoE-/- mice were divided into control group, heat wave group, and heat wave BH4 group. Mice in the heat wave and BH4 groups were exposed to simulated heat waves in the simulation chamber. Mice in BH4 group were treated with gastric lavage with BH4 2 h prior to heat wave exposure. Results showed that the heat waves did not significantly affect body weight or ET-1 levels. However, mice in the heat wave group had significantly higher rectal temperature and NO level and lower SOD activity compared with mice in the control group (p < 0.01), indicating that heat wave had negative effects on cardiac function in ApoE-/- mice. Gastric lavage with BH4 prior to heat wave exposure significantly reduced heat wave-induced increases in rectal temperature and decreases in SOD activity. Additionally, pretreatment with BH4 further increased NO level in plasma. Collectively, these beneficial effects demonstrate that BH4 may potentially mitigate the risk of coronary heart disease in mice under heat wave exposure. These results may be useful when studying the effects of heat waves on humans. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


Zhang X.,Nanjing University of Information Science and Technology | Zhang S.,Lanzhou Institute of Arid Meteorology | Wang C.,Nanjing University of Information Science and Technology | Wang B.,Lanzhou Central Meteorological Observatory | Guo P.,Nanjing University of Information Science and Technology
International Journal of Environmental Research and Public Health | Year: 2014

The effects of cold air on cardiovascular and cerebrovascular diseases were investigated in an experimental study examining blood pressure and biochemical indicators. Zhangye, a city in Gansu Province, China, was selected as the experimental site. Health screening and blood tests were conducted, and finally, 30 cardiovascular disease patients and 40 healthy subjects were recruited. The experiment was performed during a cold event during 27-28 April 2013. Blood pressure, catecholamine, angiotensin II (ANG-II), cardiac troponin I (cTnI), muscle myoglobin (Mb) and endothefin-1 (ET-1) levels of the subjects were evaluated 1 day before, during the 2nd day of the cold exposure and 1 day after the cold air exposure. Our results suggest that cold air exposure increases blood pressure in cardiovascular disease patients and healthy subjects via the sympathetic nervous system (SNS) that is activated first and which augments ANG-II levels accelerating the release of the norepinephrine and stimulates the renin-angiotensin system (RAS). The combined effect of these factors leads to a rise in blood pressure. In addition, cold air exposure can cause significant metabolism and secretion of Mb, cTnI and ET-1 in subjects; taking the patient group as an example, ET-1 was 202.7 ng/L during the cold air exposure, increased 58 ng/L compared with before the cold air exposure, Mb and cTnI levels remained relatively high (2,219.5 ng/L and 613.2 ng/L, increased 642.1 ng/L and 306.5 ng/L compared with before the cold air exposure, respectively) 1-day after the cold exposure. This showed that cold air can cause damage to patients' heart cells, and the damage cannot be rapidly repaired. Some of the responses related to the biochemical markers indicated that cold exposure increased cardiovascular strain and possible myocardial injury. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


Jiang L.,Nanjing University of Information Science and Technology | Jiang L.,Jiangsu Research Center for Ocean Survey Technology | Zhang J.,Beijing Institute of Applied Meteorology | Liu X.,Lanzhou Central Meteorological Observatory | Li F.,CAS Nanjing Institute of Geography and Limnology
Physica A: Statistical Mechanics and its Applications | Year: 2016

The spatial and temporal multi-scaling behaviors between the daily Air Temperature (AT) and the Surface Temperature (ST) over China are compared in about 60-yr observations by Multi-fractal Detrended Fluctuation Analysis (MF-DFA) method. The different fractal phenomena and diversity features in the geographic distribution are found for the AT and ST series using MF-DFA. There are more multi-fractal features for the AT records but less for ST. The respective geographic sites show important scaling differences when compared to the multi-fractal signatures of AT with ST. An interval threshold for 95% confidence level is obtained by shuffling the AT records and the ST records. For the AT records, 93% of all observed stations shows the strong multi-fractal behaviors. In addition, the multi-fractal characteristics decrease with increasing latitude in South China and are obviously strong along the coast. The multi-fractal behaviors of the AT records between the Yangtze River and Yellow River basin and in most regions of Northwest China seem to be weak and not significant, even single mono-fractal features. However, for the ST records, the geographical distributions of multi-fractal phenomenon seem to be in disorder which account for 81% of the stations. The weak multi-fractal behaviors of the ST records are concentrated in North China, most regions of Northeast China. © 2016 Elsevier B.V.


Wang J.,Institute of Arid Meteorology | Wang S.,Institute of Arid Meteorology | Zhang Q.,Institute of Arid Meteorology | Li Y.,Institute of Arid Meteorology | Zhang J.,Lanzhou Central Meteorological Observatory
Polish Journal of Environmental Studies | Year: 2015

In this study, taking drought disaster-causing factors like precipitation, temperature, reference evapotranspiration, and the degree of drought severity based on the drought index as study objects, the characteristics of these above elements against the background of global warming were analyzed by using the method of climate statistics. The data include a variety of climate observations of 129 meteorological stations in southwestern and southern China from 1961 to 2012. The results show that over the past half century sustained temperature increase has been presented in the study area against the background of global warming. However, there is still a sharp warming point (mutation point) of temperature time series that occurred in 1994 during 1961 to 2012 according to the Mann-Kendal test. In other words, the past half century could be divided into two episodes with the year 1994 as the boundary: the first period (i.e. the period before significant temperature rise) from 1961 to 1994, and the second period (i.e. the period after significant temperature rise) from 1995 to 2012. In order to highlight the effects that result from obvious warming, a comparison of the above factors between the two episodes and the trend of these factors in the two episodes are analyzed. This shows that, during the period after significant temperature rise, the study area has experienced a significant downward trend in precipitation and a decline in reference evapotranspiration, but a rise in its change trend, and more serious degree of drought severity due to the impact of less precipitation and higher temperatures. © 2015, Polish Journal of Environmental Studies. All rights reserved.


Luo B.,Nanjing University of Information Science and Technology | Luo B.,Lanzhou Institute of Arid Meteorology | Zhang S.,Lanzhou Institute of Arid Meteorology | Ma S.,Nanjing University of Information Science and Technology | And 2 more authors.
International Journal of Environmental Research and Public Health | Year: 2012

The purpose was to investigate the effects of artificial cold air on cardiovascular risk in hypertensive subjects. An artificial cold air was simulated with hourly ambient temperature data of a real moderate cold air in China. Twenty-four male SHR rats were randomly divided into the minimum temperature (Tmin) group, the rewarming temperature (Tr) group and two concurrent control groups with six rats in each (Tmin and Tr represent two cold air time points, respectively). Tmin and Tr groups were exposed to the cold air that was stopped at Tmin and Tr, respectively. After cold air exposure, blood pressure, heart rate and body weight were monitored, blood was collected for the detection of some indexes like fibrinogen, total cholesterol and uric acid. Results demonstrated that blood pressure, whole blood viscosity, blood fibrinogen, total cholesterol and uric acid increased significantly both in the Tmin and Tr groups; low density lipoprotein/high density lipoprotein increased significantly only in Tr group; there was higher level of blood fibrinogen in the Tr group than the Tmin group; higher levels of creatine kinase-MB was found in both the Tmin and Tr groups. These results suggest that cold air may increase the cardiovascular risks in hypertensive subjects indirectly through its effects on the sympathetic nervous system and renin angiotensin system, blood pressure and atherosclerosis risk factors like blood viscosity and fibrinogen, lipids and uric acid in the blood.© 2012 by the authors; licensee MDPI, Basel, Switzerland.


Luo B.,Nanjing University of Information Science and Technology | Luo B.,Lanzhou Institute of Arid Meteorology | Zhang S.,Lanzhou Institute of Arid Meteorology | Ma S.,Nanjing University of Information Science and Technology | And 2 more authors.
International Journal of Environmental Research and Public Health | Year: 2012

The purpose of this study is to explore possible potential implications of cold air in cardiovascular disease (CVD) risk in rats. Healthy Wistar rats were exposed to artificial cold air under laboratory conditions, and their systolic blood pressure, heart rate, vasoconstriction, CVD risk factors, and myocardial damage indicators after cold air exposure were determined and evaluated. Systolic blood pressure, whole blood viscosity, and plasma level of norepinephrine, angiotensin II, low density lipoprotein, total cholesterol, and fibrinogen in treatment groups increased significantly compared with control groups. No significant variations were found in plasma Mb and cTnT and myocardial tissue between the treatment and control groups. Results indicate that: (1) higher levels of SBP, WBV and LDL/HDL, total cholesterol (TC), and FG in blood may indicate higher CVD risks during cold air exposure; (2) cold air may exert continuous impacts on SBP and other CVD risk factors. © 2012 by the authors; licensee MDPI, Basel, Switzerland.


Zhang Y.,Lanzhou University | Zhang Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Tian Q.,Chinese Academy of Meteorological Sciences | Gou X.,Lanzhou University | And 3 more authors.
International Journal of Climatology | Year: 2011

A millennium-long tree-ring-width chronology from the middle Qilian Mountains in northwestern China has been used to reconstruct annual precipitation variation (from the prior August to current July) since AD 775. The reconstruction explains 37.8% of variance of the observed data. Based on the mean and standard deviation of the reconstructed series, several prolonged severe dry and wet periods were indentified: drought spells in AD 1144-1154 (11 years) and 1925-1932 (8 years) and wet spells in AD 985-999 (15 years), 1089-1097 (9 years) and 1979-1991 (12 years). Both multi-taper spectral analysis (MTM) and wavelet analysis suggest that periods of the reconstructed precipitation are consistent with those associated with the Asian Summer Monsoon and perhaps solar activity. Copyright © 2010 Royal Meteorological Society.


Luo B.,Nanjing University of Information Science and Technology | Luo B.,Lanzhou Institute of Arid Meteorology | Zhang S.,Lanzhou Institute of Arid Meteorology | Ma S.,Nanjing University of Information Science and Technology | And 2 more authors.
International Journal of Biometeorology | Year: 2014

Ten-week-old male Wistar rats (systolic blood pressure, 106-116 mmHg; body weight, 300-320 g) and spontaneously hypertensive rats (systolic blood pressure, 160-176 mmHg; body weight, 210.9-244.9 g) were used as healthy and hypertensive subjects to determine the effects of varying degrees of cold-air exposure in a climate chamber box. The three cold-air ranks were cold air I [minimum temperature (TMIN) 6.4 °C, ↓{increment}T48 8.6 °C], cold air II (TMIN 3.8 °C, ↓{increment}T48 11.2 °C), and cold air III (TMIN -0.3 °C, ↓{increment}T48 15.3 °C), as established from the cold-air data of Zhangye City, China. Each cold-air rank consisted of a temperature drop and a temperature increase with the same initial and terminal temperatures (15 °C). After cold-air exposure, the risk factors for cardiovascular disease (CVD) such as systolic blood pressure, whole blood viscosity (10/s and 150/s), plasma fibrinogen, and blood lipids of the rats were determined. The results indicated that the CVD risk factors of the healthy and hypertensive rats increased significantly with cold-air exposure intensities. The increase in systolic blood pressure was greater during temperature drops, whereas the increases in whole blood viscosity and plasma fibrinogen were greater after cold-air exposure. The effects of cold-air exposure on the CVD risk factors of healthy rats, particularly the systolic blood pressure, whole blood viscosity (150/s), and LDL/HDL, were greater than those in hypertensive rats. In conclusion, CVD risk may increase with cold-air ranks. Blood pressure-induced CVD risk may be greater during cold-air temperature drop, whereas atherosclerosis-induced CVD risk may be greater after cold-air exposure. The effect of cold air on the CVD risk factors in healthy subjects may be more significant than those in hypertensive subjects. © 2013 ISB.


PubMed | Lanzhou Institute of Arid Meteorology, Lanzhou Central Meteorological Observatory and Nanjing University of Information Science and Technology
Type: Journal Article | Journal: International journal of environmental research and public health | Year: 2014

The effects of cold air on cardiovascular and cerebrovascular diseases were investigated in an experimental study examining blood pressure and biochemical indicators. Zhangye, a city in Gansu Province, China, was selected as the experimental site. Health screening and blood tests were conducted, and finally, 30 cardiovascular disease patients and 40 healthy subjects were recruited. The experiment was performed during a cold event during 27-28 April 2013. Blood pressure, catecholamine, angiotensin II (ANG-II), cardiac troponin I (cTnI), muscle myoglobin (Mb) and endothefin-1 (ET-1) levels of the subjects were evaluated 1 day before, during the 2nd day of the cold exposure and 1 day after the cold air exposure. Our results suggest that cold air exposure increases blood pressure in cardiovascular disease patients and healthy subjects via the sympathetic nervous system (SNS) that is activated first and which augments ANG-II levels accelerating the release of the norepinephrine and stimulates the renin-angiotensin system (RAS). The combined effect of these factors leads to a rise in blood pressure. In addition, cold air exposure can cause significant metabolism and secretion of Mb, cTnI and ET-1 in subjects; taking the patient group as an example, ET-1 was 202.7 ng/L during the cold air exposure, increased 58 ng/L compared with before the cold air exposure, Mb and cTnI levels remained relatively high (2,219.5 ng/L and 613.2 ng/L, increased 642.1 ng/L and 306.5 ng/L compared with before the cold air exposure, respectively) 1-day after the cold exposure. This showed that cold air can cause damage to patients heart cells, and the damage cannot be rapidly repaired. Some of the responses related to the biochemical markers indicated that cold exposure increased cardiovascular strain and possible myocardial injury.

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