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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. Source


Zhang Y.,Lanzhou University | Wang S.,Lanzhou University | Li J.,Lanzhou University | Du L.,Lanzhou University | Liu K.,Lanzhou Central Meteorological Observatory
2011 International Conference on Electrical and Control Engineering, ICECE 2011 - Proceedings | Year: 2011

The climatic characteristics of precipitation in different grade at Maqu between 1967 and 2008 were analyzed by using the data of daily precipitation and temperature from Maqu and surrounding meteorological stations. The climatic characteristics of different grade precipitation at the time scales of pentad, ten days, month and year in Maqu has been studied by using the linear tendency evaluation, Morlet continuous wavelet transform and the other methods. The results show that: Maqu, as the test areas about rain stimulation by artifical means, its characteristics of precipitation can be used to represent the surrounding areas. With global warming, precipitation of Maqu and Maqu regions gradually decreases. The starting and ending date of storm rain in Maqu, which located in northeast side of Tibet plateau, were later than that in Pingliang, which located in southeast of Gansu province. Maqu precipitation is relatively less during mid-July to mid-August (from the 39th to 46th pentad), but have a relative peak in the 42th pentad. The starting date of the moderate rain was being became earlier with time, the ending date of the moderate rain had little changed. © 2011 IEEE. Source


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. Source


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. Source


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. Source

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