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Under global warming, the climate in semi-arid inland Eurasia (SAIE) has changed in an opposite manner, thereby seriously impacting the local ecological environment. However, the key influencing factors and physical mechanism remain inconclusive. In this paper, we remodel the precipitation recycling ratio (PRR) model to assess the contributions of moisture from different water vapor sources to local precipitation, analyze the characteristics of the PRR and precipitation in SAIE, and provide possible physical reasons based on the Clausius–Clapeyron equation. It is found that the PRR increased from 1970 to 2017 as the result of linear trend analysis, with obvious seasonality. Moreover, the component of precipitation contributed by locally evaporated moisture (Pl), and that contributed by advected moisture (Pa) as well as the total precipitation (P), increased during the past 48 years. In particular, the Pa, Pl, and P in autumn and winter all increased obviously during the past 20 years from the interdecadal change trend, as well as the PRR (Pl/P), which was opposite to the decrease in the total water vapor input I(Ω) in the horizontal direction. According to the Clausius–Clapeyron equation, one of the causes might be that global warming has accelerated the local water cycle and driven the increase in Pa, and the increase in atmospheric water holding capacity caused by global warming provides the power source. We suggest that the climate’s transformation from dry to wet in SAIE can only be temporary since SAIE is an inland area and the adjustment of atmospheric circulation did not lead to the increase in external water vapor.

How to improve the subseasonal forecast skills of dynamic models has always been an important issue in atmospheric science and service. This study proposes a new dynamical-statistical forecast method and a stable components dynamic statistical forecast (STsDSF) for subseasonal outgoing long-wave radiation (OLR) over the tropical Pacific region in January-February from 2004 to 2008. Compared with 11 advanced multi-model ensemble (MME) daily forecasts, the STsDSF model was able to capture the change characteristics of OLR better when the lead time was beyond 30 days in 2005 and 2006. The average pattern correlation coefficients (PCC) of STsDSF are 0.24 and 0.16 in 2005 and 2006, while MME is 0.10 and 0.05, respectively. In addition, the average value of PCC of the STsDSF model in five years is higher than MME in 7–11 pentads. Although both the STsDSF model and MME show a similar temporal correlation coefficient (TCC) pattern over the tropical Pacific region, the STsDSF model error grows more slowly than the MME error during 8–12 pentads in January 2005. This phenomenon demonstrates that STsDSF can reduce dynamical model error in some situations. According to the comparison of subseasonal forecasts between STsDSF and MME in five years, STsDSF model skill depends strictly on the predictability of the dynamical model. The STsDSF model shows some advantages when the dynamical model could not forecast well above a certain level. In this study, the STsDSF model can be used as an effective reference for subseasonal forecast and could feasibly be used in real-time forecast business in the future.

Global warming weakened the summer monsoon and increased the evaporation, leading to more contribution of local evaporation moisture to the local precipitation for the monsoon areas. However, the descriptions of the contribution of the local moisture to the total precipitation and its characteristics have not been known very well. In this paper, taking the middle and lower Reaches of the Yangtze River (MLRYR) as a case and using the precipitation recycling process model, we analyzed the characteristics of the contribution of the local moisture to the total precipitation and the possible reasons. The results show that: the seasonal difference in precipitation recycling rates is obvious, the precipitation recycling rates in spring and summer are small (18.30% and 19.30%), the maximum in autumn is 30.50%, and the precipitation recycling rates in all seasons except summer show a significant upward trend (about 1.70%/10a). Additionally, the water vapor input into MLRYR from four boundaries significantly reduced except for the eastern boundary, and the water vapor contribution from the South and East borders is in summer, and the water vapor contribution from the North and West borders is in autumn, winter and spring. We suggest that the model of the precipitation recycling rate is important to evaluate the contribution of different water vapor sources, and help to further improve the ability of river water prediction in flood season.

The precipitation recycling rate (PRR) is an important index when trying to understand the physical mechanisms behind the effects of different sources of water vapor on regional precipitation. We studied the change in the PRR in the mid- and lower reaches of the Yangtze River (MLRYR), the correlation between the PRR and the external source of water vapor and local evaporation, and the possible reasons for the interannual variation of the PRR. Our study was based on an evaluation model of the PRR and used precipitation data from meteorological stations in China and NCEP/NCAR reanalysis datasets. Our results show that the mean PRR in the MLRYR for the time period 1961–2017 was largest in autumn (about 0.3) and smallest in summer (about 0.23), with a clear upward trend (passed the 95% significance F-test), except in summer. The highest trend coefficient of the PRR was in autumn (0.38), indicating that the contribution of an external source of water vapor to local precipitation was reduced. The PRR of the MLRYR was strongly correlated with the input of water vapor through the western and southern boundaries. Water vapor was mainly sourced from the Northwest Pacific Ocean, the South China Sea and the Bay of Bengal. The anomalous Northwest Pacific cyclone induced by the Pacific sea surface temperature restrained the input of water vapor into the MLRYR from the Western Pacific, the South China Sea and the Bay of Bengal, contributing to the upward trend in the PRR. We suggest that increases in the sea surface temperature in the Pacific Ocean, South China Sea and especially the Indian Ocean will have an important impact on precipitation in East Asia.

Global warming accelerates water cycle with features of regional difference. However, little is known about the physical mechanism behind the phenomenon. To reveal the links between water cycle and climatic environment, we analyzed the changes of water cycle elements and their relationships with climatic and environmental factors. We found that when global warming was significant during the period of 1986-2003, the precipitation in Tarim mountains as well as Xinjiang increased rapidly except for Tarim plains, which indicated that there existed a signal of acceleration for water cycle in Xinjiang. The speed of water cycle is mainly affected by altitude, latitude, longitude, slope direction, and the most fundamental element is temperature. Moreover, according to Clausius-Kela Bai Lung relation, we found that the climate change induced the increase of temperature and accelerated the local water cycle only for the wet places. Our results provide a possible physical mechanisms of water cycle and thus well link the climate change to water circulation.

Using the multielements similarity measurement method and 1950-2017 NCEP/NCAR gridded daily reanalysis datasets, we analyzed season duration in China during 1950-2016, and we defined the element with maximum absolute sensitivity as the key impact element at each point using the sensitivity analysis method. The decadal change of season duration and its key impact element before and after 1980 were studied. The results indicated obvious meridional and zonal differences in the distribution of season duration for the 67-year average, and that the key impact element has the same distribution characteristics as season duration. In addition, complementary relationships were found between the durations of spring and summer, autumn and winter, and the cold and warm seasons. Among them, the complementary relationship between the durations of spring and summer was strongest and the regions of complementarity were numerous. The complementary regions of autumn and winter durations were found mainly in western China. In the cold and warm seasons, the complementary regions were widespread and the complementary relationship was generally weak. Comparison of the periods before and after 1980 revealed an east-west difference in the interdecadal variation of season duration. Interdecadal variation in spring and summer was found concentrated in northern and western regions, while that in autumn and winter was concentrated in the western region. Areas of significant interdecadal variation of the key elements were found concentrated in northern and western regions, corresponding well to the areas of significant interdecadal variation of season duration. [ABSTRACT FROM AUTHOR]

In this study, the winter-summer-winter seasonal variation characteristics of the atmospheric temperature in northern East Asia (NEA) during the past 60 years are analyzed. The results revealed a type of new seasonal variation mechanism of temperature: winter-winter recurrence (WWR). This study initially discussed the formation mechanism of WWR from the angle of the relationship between the WWR and the atmospheric internal factors and external forcing. The main conclusions are summarized as follows: (1) The winter-summer-winter continuous variation of the AO anomaly index has consistent characteristics with the atmospheric variation of the WWR in the NEA, and their 60-year correlation coefficient reaches 0.43, passing the 95% significance level. It is indicated that the seasonal anomaly of the AO has a certain influence on the WWR; (2) Overall, the PDO maintains a negative phase in the negative WWR years, while it displays the opposite feature in the positive WWR years. The negative (positive) anomaly of PDO is favourable to the occurrence of sustainable low (high) temperatures in the NEA, and may be the important external driving factor for motivating the WWR in the NEA; (3) The binary regression, based on the PDO and AO indexes successfully reproduces the curve of TWWR-HG, which is significantly correlated with the WWR index TWWR, and can reproduce the time-height profile of the WWR characteristics from 400 to 1,000 hPa. Therefore, it is concluded that the WWR of the atmospheric temperatures in the NEA is the result of the combined action of the PDO and AO. [ABSTRACT FROM AUTHOR]

Based on nonlinear prediction and information theory, vertical heterogeneity of predictability and information loss rate in geopotential height field are obtained over the Northern Hemisphere. On a seasonal-to-interannual time scale, the predictability is low in the lower troposphere and high in the mid-upper troposphere. However, within mid-upper troposphere over the subtropics ocean area, there is a relatively poor predictability. These conclusions also fit the seasonal time scale. Moving to the interannual time scale, the predictability becomes high in the lower troposphere and low in the mid-upper troposphere, contrary to the former case. On the whole the interannual trend is more predictable than the seasonal trend. The average information loss rate is low over the mid-east Pacific, west of North America, Atlantic and Eurasia, and the atmosphere over other places has a relatively high information loss rate on all-time scales. Two channels are found steadily over the Pacific Ocean and Atlantic Ocean in subtropics. There are also unstable channels. The four-season influence on predictability and information communication are studied. The predictability is low, no matter which season data are removed and each season plays an important role in the existence of the channels, except for the winter. The predictability and teleconnections are paramount issues in atmospheric science, and the teleconnections may be established by communication channels. So, this work is interesting since it reveals the vertical structure of predictability distribution, channel locations, and the contributions of different time scales to them and their variations under different seasons. [ABSTRACT FROM AUTHOR]

In this paper we try to extract stable components in the extended-range forecast for the coming 10–30 days by using empirical orthogonal function (EOF) analysis, similarity coefficient, and some other methods based on the National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis daily data. The comparisons of the coefficient of variance of climatological background field and truth data in winter between 2010 and 2011 are made. The method of extracting stable components and climatological background field can be helpful to increase forecasting skill. The forecasting skill improvement of air temperature is better than geopotential height at 500 hPa. Moreover, this method improves the predictability better in the Pacific Ocean. In China, the forecast in winter in Northeast China is more uncertain than in the other parts. [ABSTRACT FROM AUTHOR]

Objective: Through the establishment of abortion model caused by embryo implantation difficulties, exploring the role of Yun Kang oral liquid in protecting embryos., Methods: The pregnant rats were divided into 6 groups:normal control group (NC), model group (MG), dydrogesterone group (DT), and three dose groups of low, medium and high levels of Yun Kang oral liquid (YK-L, YK-M, YK-H), 11 in each group.From the first day of pregnancy, daily intragastric administration, the dose of DT group was 3.02 mg/kg, and the doses of Yun Kang oral liquid were 4, 6, and 9 ml/kg, respectively.The rats in NC and MG were treated with an equal volume of purified water for 10 days.On the third day of pregnancy, except for the NC group, the other groups were injected with mifepristone subcutaneously at the back of the neck at a dose of 5 mg/kg to cause an embryo implantation barrier model.On the 10th day of pregnancy, blood was collected from the abdominal aorta in each group.Serum follicle stimulating hormone (FSH), interferon-γ (IFN-γ) and interleukin (IL-4) were measured by enzyme-linked immunosorbent assay.The number of embryo implantation was observed in the uterus, and the pathological changes of the uterus were observed by HE staining., Results: Compared with the NC group, the number of embryo implantation and the serum levels of FSH and IL-4 in the MG group were decreased significantly ( P < 0.05, 0.01), and pathological changes such as uterine glandular epithelial hyperplasia and inflammatory cell infiltration in the glandular cavity were observed.Compared with MG group, the number of embryo implantation and serum FSH and IL-4 levels of rats in YK-M and YK-H groups were increased significantly ( P <0.05, 0.01).The pathological changes such as uterine glandular epithelial hyperplasia and inflammatory cell infiltration in the gland were also improved.There was no significant difference in serum IFN-γ levels between the groups., Conclusions: Yun Kang oral liquid may improve the endometrial pathological changes and increase the number of embryo implantation by increasing the levels of serum sex hormone FSH and immune cytokine IL-4 in embryo implantation impediment rats.

In the present paper the fluorescence spectra of the blood serum excited with different wavelength were measured with the fluorescence photometer RF5301 (SHIMADZU) made in Japan. The relationship between the fluorescence spectra of the serum and the wavelength of the excitation light was studied during the experiment. The experimental results show that the linetype and peak wavelength of the fluorescence spectra of serum excited by ultraviolet radiation with different wavelength are almost the same, and they do not depend on the excitation wavelength. But the fluorescence peak value changes with the excitation wavelength. There are two high intensity emission intervals in the fluorescence spectra. One of these is from about 300 nm to 410 nm, and the other is below 310 nmr The fluorescence spectra are mostly centralized in the first interval, and the wavelengths of fluorescence peaks were found around two locations: one is near 330 nm and the other is near 370 nm. At this time the strife phenomena occur. When the excitation wavelength is about 250 nm or higher, the fluorescence peak only occurs at 330 nm, and the optimal excitation wavelength is 300 nm. While the wavelength is greater than 320 nm, the fluorescence intensity of the first interval begins to fall, while that of the other augments. And at this time the peak of wavelength of fluorescence is 452 nm. This study provides the experimental foundations for advanced study and applications of the characteristics of fluorescence spectrum of blood serum, and also offers the references to the wavelength selection of excitation light in the application of the photo-induced fluorescence spectra diagnostic technology.

The analysis technique of fluorescence is adopted to study the intensity of excitation fluorescence of blood in the present paper. The theoretical analysis and differences of normal and abnormal blood (hyperglycemia, hyperlipemia) are presented. The theoretical analysis was proved by experiment results. It was discovered that blood sugar consistency has an effect on blood fluorescence. In other words, with the same excitation wavelength and with blood sugar consistency increasing, the fluorescence intensity increases gradually. It is obvious that blood sugar is also a kind of fluorescein, and its consistency has an effect on fluorescence intensity, which is identical with the theoretical analysis, indicating that the experiment is successful, and it is possible to distinguish blood sugar consistency by comparing the fluorescence intensity in blood. It was also discovered that the higher the cholesterin content, the more intense the fluorescence. When excitation wavelength is especially 435 nm, the phenomenon is very obvious. The study paves a new way for the blood quick check and diagnosis of diseases.