Anomaly In China Research Articles

Zonal shift of the South Asian High on the subseasonal time‐scale and its relation to the summer rainfall anomaly in China

By using daily National Centers for Environmental Prediction‐National Center for Atmospheric Research (NCEP‐NCAR) reanalysis and observed rainfall data, we investigated the east–west shift of the South Asian High (SAH) on the subseasonal time‐scale and its relationship with the rainfall anomaly in China. It is found that the zonal shift of the SAH at 200 hPa displays a dominant periodicity of 10–50 days, with two preferred locations, one over the northeast Tibetan Plateau (eastern location) and the other over the northeast Iranian Plateau (western location). The zonal shift of the SAH is closely related to the southward movement of intraseasonal perturbations originating in middle latitudes. A vorticity budget analysis reveals that the advection of mean vorticity by the perturbation of meridional wind primarily contributes to the vorticity tendency over both the eastern and western locations. The zonal shift of the SAH closely connects to the summer rainfall anomalies over China. An eastern (a western) location of the SAH corresponds to generally positive (negative) rainfall anomalies in northwestern China and negative (positive) anomalies in southern China. A further diagnosis reveals that the strengthening of the intraseasonal perturbation during the southward journey in the eastern location is attributed to a positive convection–circulation feedback. On the one hand, a positive geopotential height anomaly in the upper troposphere and associated upper‐level divergence induce anomalous ascending motion and condensational heating in the middle troposphere. On the other hand, the positive heating anomaly increases mid‐tropospheric temperature and strengthens upper‐level geopotential height. The southward propagation leads to the zonal shift of the SAH.

An assessment of the atmospheric centers of action in the northern hemisphere winter

In the northern hemisphere, there are six permanent or semi-permanent atmospheric activity centers, namely the Icelandic Low, Aleutian Low, India Low, Mongolia High, North Pacific High, and North Atlantic High. The first four are semi-permanent action centers and the last two are permanent circulation systems. The India Low exists only during the summer. By using 160 years (1850–2009) of monthly mean sea level pressure data from the Hadley Centre in the UK, we conduct a comprehensive study of the five boreal winter atmospheric centers of action (ACAs). Based on a unified definition and a method determined in previous studies, we calculate the indices of areal coverage (S), intensity (P), and position of action center (λ c, φ c) for each of these five ACAs. Through an in-depth analysis of these indices and their relationships with climate variables, we evaluate the indices by describing and explaining areal climate anomalies, particularly precipitation and temperature anomalies in China. We show that (1) ACAs significantly influence the climate anomalies of surrounding areas (2) the influences of oceanic ACAs are larger and the intensity anomalies of ACAs have a greater impact than their location displacement, and (3) ACAs exert more control on temperature than they do on precipitation. For the two ACAs over the north Atlantic, the impacts of their intensities on the anomalies of temperature and precipitation are similar. For the two ACAs over the north Pacific, their influences are almost the opposite. The most influential ACA for climate anomalies in China during the boreal winter is HMO. When HMO is stronger, China has a colder winter and it is wetter in the north. With stronger ACAs in the upstream, i.e., the Icelandic Low and North Atlantic High, northern China has a warmer winter. The ACAs over the north Pacific exert little influence on climate anomalies in China during winter. The analyses presented in this paper provide a set of useful indices for defining and describing ACAs, and they suggest insightful applications for these indices.

Predictability of winter temperature in China from previous autumn Arctic sea ice

The potential predictability of winter temperature in China from autumn Arctic sea ice anomalies is studied by examining and statistically modeling the large–scale interannual covariability between them on the basis of singular value decomposition analysis. It is demonstrated that an intimate relationship exists between September and October sea ice anomalies in the Eurasian Arctic and following winter temperature anomalies in China, except in the Tibetan Plateau. When the autumn sea ice anomalies decline in the Eurasian Arctic, above-normal pressure anomalies appear to prevail over the region from the Eurasian Arctic to Eastern Europe and Mongolia, and below-normal anomalies prevail over the mid-latitudes of Asia and Northwestern Pacific in the following winter. Consequently, the winter Siberian High and East Asian trough are both strengthened, favoring the southward invasion of high–latitude cold air masses and thus cold temperature anomalies in China. It is found that the Siberian High plays a crucial role in delivering effects of the autumn Arctic sea ice anomalies on winter temperature variability in China. Based on this evidence, a statistical model is established to examine the potential predictability of winter temperature anomalies in China by taking the autumn Arctic sea ice signals as a predictor. Validation shows considerable skill in predicting winter temperature anomalies over a large part of China, indicating a significant potential for improving winter climate prediction in China.

Variability in crop yields associated with climate anomalies in China over the past three decades

We used simple and explicit methods, as well as improved datasets for climate, crop phenology and yields, to address the association between variability in crop yields and climate anomalies in China from 1980 to 2008. We identified the most favourable and unfavourable climate conditions and the optimum temperatures for crop productivity in different regions of China. We found that the simultaneous occurrence of high temperatures, low precipitation and high solar radiation was unfavourable for wheat, maize and soybean productivity in large portions of northern, northwestern and northeastern China; this was because of droughts induced by warming or an increase in solar radiation. These climate anomalies could cause yield losses of up to 50 % for wheat, maize and soybeans in the arid and semi-arid regions of China. High precipitation and low solar radiation were unfavourable for crop productivity throughout southeastern China and could cause yield losses of approximately 20 % for rice and 50 % for wheat and maize. High temperatures were unfavourable for rice productivity in southwestern China because they induced heat stress, which could cause rice yield losses of approximately 20 %. In contrast, high temperatures and low precipitation were favourable for rice productivity in northeastern and eastern China. We found that the optimum temperatures for high yields were crop specific and had an explicit spatial pattern. These findings improve our understanding of the impacts of extreme climate events on agricultural production in different regions of China.

Skewness Preference and IPO Anomalies in China

Due to investors' unique structure and new transaction share rules, speculation in China's IPO market is common. In this paper, we investigate many anomalies in IPOs that produce huge initial return, long-term return reversal and high turnover rate from the perspective of investors' desire to gamble (skewness preferences). Based on Cumulative Prospect Theory, this paper theoretically and empirically verified that there is a significant impact on first day and long-term returns. Using all issued IPO between 2009 and 2012 as a study sample, the empirical results show that the increase of a standard deviation of skewness preference, and the first day returns increase 5.478%. Moreover, when the market environment is favorable, the positive sentiment of investors will make the effect of skewness preferences stronger. In the long run, the stronger the expected skewness is, the more negative the long-term risk premium is, and the lower the possibility of new shares that institutional investors continue to hold. In addition, skewness preferences across different industries, different financing scale, and different issue price has a significant difference.

Real Exchange Rate Anomalies in China: Sterilization by the People and Trade Liberalization

Real Exchange Rate Anomalies in China: Sterilization by the People and Trade Liberalization

The cooperative impacts of the El Niño-Southern Oscillation and the Indian Ocean Dipole on the interannual variability of autumn rainfall in China

The El Nino-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) are high degree synergic air-sea interactions greatly affecting the interannual variability of rainfall in China. This study reveals the possible cooperative impacts of the ENSO and IOD on boreal autumn rainfall anomalies in China, on the basis of data analysis collected during 1951-2010. Our results suggest that the positive phase of the combined ENSO and IOD events may result in an anomalous lower-level anticyclone over the western North Pacific (WNP) region, with a southward shift of the strengthened East Asian jet stream (EAJS). An enhanced moisture supply is transported to increase autumn rainfall over southern China by the southwesterly winds. In the negative phase, however, southerly anomalies are observed between the anomalous cyclone and anticyclone over the Indo-China Peninsula and the WNP, which carry more moisture to the Loess Plateau (LP) area with a northward shift of the weakened EAJS, leading to an increase of autumn rainfall in this area. Note that the negative IOD plays an important role in the cooperative influences on the autumn rainfall anomalies over the LP in that the associated anomalous lower-level cyclone shifts westward compared to the impacts of the pure La Nina. The regional asymmetric responses of autumn rainfall to the positive and negative phases of the ENSO and IOD could be attributed to the different responses of lower-level circulation over WNP and the meridional shift of the upper-level EAJS. Results demonstrate that the combined ENSO and IOD induce an anomalous zonal gradient of sea surface temperature (SST) over the tropical Indo-Pacific Ocean to alter the convection anomalies over the Indo-Pacific warm pool that further affect the upper and lower atmospheric circulations by means of a Rossby wave response.

Contrasting Impacts of the Arctic Oscillation on Surface Air Temperature Anomalies in Southern China between Early and Middle-to-Late Winter

AbstractIn the boreal winter, the Arctic Oscillation (AO) evidently acts to influence surface air temperature (SAT) anomalies in China. This study reveals a large intraseasonal variation in the relationship between the winter AO and southern China SAT anomalies. Specifically, a weak in-phase relationship occurs in December, but a significant out-of-phase relationship occurs in January and February. The authors show that the linkage between the AO and southern China SAT anomalies strongly depends on the AO-associated changes in the Middle East jet stream (MEJS) and that such an AO–MEJS relationship is characterized by a significant difference between early and middle-to-late winter. In middle-to-late winter, the Azores center of high pressure anomalies in the positive AO phase usually extends eastward and yields a significantly anomalous upper-level convergence over the Mediterranean Sea, which can excite a Rossby wave train spanning the Arabian Sea and intensify the MEJS. In early winter, however, the Azores center of the AO is apparently shifted westward and is mainly confined to the Atlantic Ocean; in this case, the associated change in the MEJS is relatively weak. Both observational diagnoses and experiments based on a linearized barotropic model suggest that the MEJS is closely linked to the AO only when the latter generates considerable upper-level convergence anomalies over the Mediterranean Sea. Therefore, the different impacts of the AO on the MEJS and the southern China SAT anomalies between early and middle-to-late winter are primarily attributed to the large intraseasonal zonal migrations of the Azores center of the AO.

Connections between the Eurasian teleconnection and concurrent variation of upper-level jets over East Asia

The variation of the East Asian jet stream (EAJS) associated with the Eurasian (EU) teleconnection pattern is investigated using 60-yr NCEP-NCAR daily reanalysis data over the period 1951–2010. The EAJS consists of three components: the polar front jet (PFJ); the plateau subtropical jet (PSJ); and the ocean subtropical jet (OSJ). Of these three jets over East Asia, the EU pattern exhibits a significant influence on the PFJ and OSJ. There is a simultaneous negative correlation between the EU pattern and the PFJ. A significant positive correlation is found between the EU pattern and the OSJ when the EU pattern leads the OSJ by about 5 days. There is no obvious correlation between the EU pattern and the PSJ. The positive EU phase is accompanied by a weakened and poleward-shifted PFJ, which coincides with an intensified OSJ. A possible mechanism for the variation of the EAJS during different EU phases is explored via analyzing the effects of 10-day high-and low-frequency eddy forcing. The zonal wind tendency due to high-frequency eddy forcing contributes to the simultaneous negative correlation between the EU pattern and the PFJ, as well as the northward/southward shift of the PFJ. High- and low-frequency eddy forcing are both responsible for the positive correlation between the EU pattern and the OSJ, but only high-frequency eddy forcing contributes to the lagged variation of the OSJ relative to the EU pattern. The negative correlation between the EU pattern and winter temperature and precipitation anomalies in China is maintained only when the PFJ and OSJ are out of phase with each other. Thus, the EAJS plays an important role in transmitting the EU signal to winter temperature and precipitation anomalies in China.

A study of GPS ionospheric scintillations observed at Shenzhen

Ionospheric scintillation variations are studied using GPS measurements at the low latitude station of Shenzhen (22.59°N,113.97°E), situated under the northern crest of the equatorial anomaly region, from the Chinese Meridian Project. The results are presented for data collected during the current phase of rising solar activity (low to high solar activity) from December 2010 to April 2014. The results show that GPS scintillation events were largely a nighttime phenomenon during the whole observation period. Scintillation events mainly occurred along the inner edge of the northern crest of the equatorial anomaly in China. The occurrence of scintillations in different sectors of the sky was also investigated, and the results revealed that it is more likely for the scintillations to be observed in the west sector of the sky above Shenzhen. During the present period of study, a total number of 512 total electron content (TEC) depletions and 460 lock loss events were observed. In addition, both of these events are likely to increase during periods of high solar activity, especially because the strong scintillations are often simultaneously accompanied by TEC depletions and lock losses by GPS receivers.

Evolution of Eurasian teleconnection pattern and its relationship to climate anomalies in China

The Eurasian teleconnection pattern (EU) is a major mode of low-frequency variability in the Northern Hemisphere winter, with notable impacts on the temperature and precipitation anomalies in Eurasia region. To investigate the structure, life cycle and dynamical mechanisms of EU pattern, diagnostic analyses are conducted to clarify EU pattern evolution, with an emphasis on EU development and decay. In the developing stage, a geopotential height anomaly over North Atlantic emerges 6 days before EU peak phase and other three geopotential height anomalies appear one by one in the following days. During this period, all geopotential height anomalies experience considerable growth and the four-center structure of EU pattern forms 2 days before peak phase. The obvious wave train structure appears at 300 hPa. The EU pattern growth is driven by both relative vorticity advection and transient eddy fluxes. After the peak phase, the geopotential height anomaly over North Atlantic becomes weak as it decays earlier than other anomaly centers, which leads to the classic three-center structure of EU teleconnection pattern. The complete life cycle of EU pattern experience considerable growth and decay within 10 days. During the decaying stage, the horizontal divergence and the transient eddy fluxes play important roles. Additionally, the relationship of EU pattern to winter climate anomalies in China is also analyzed focusing on the decaying stage. The impact of EU pattern on temperature and precipitation in China are significant in 2–4 days after EU peak phase and the distribution of temperature and precipitation anomaly has obvious regional differences.

Different relationships between spring SST in the Indian and pacific oceans and summer precipitation in China

Observational and reanalysis data are used to investigate the different relationships between boreal spring sea surface temperature (SST) in the Indian and Pacific oceans and summer precipitation in China. Partial correlation analysis reveals that the effects of spring Indian Ocean SST (IO SST) and Pacific SST (PSST) anomalies on summer precipitation in China are qualitatively opposite. When IO SST anomalies are considered independently of PSST anomalies, precipitation decreases south of the Yangtze River, in most areas of Inner Mongolia, and in some parts of Liaoning Province, and increases in the Yangtze River valley, parts of southwestern and northern China, northeastern Inner Mongolia, and Heilongjiang Province. This results in a negative-positive-negative-positive pattern of precipitation anomalies in China from south to north. When PSST anomalies (particularly those in the Nino3.4 region) are considered independently of IO SST anomalies, the pattern of precipitation anomalies in China is positive-negative-positive-negative from south to north. The genesis of summer precipitation anomalies in China is also examined when El Nino-Southern Oscillation (ENSO) signals are removed from the ocean and atmosphere. An anticyclonic low-level wind anomaly forms in the South China Sea-Northwest Pacific area when the IO SST anomaly (SSTA) is warm and the Northwest Pacific SSTA is cold. This anticyclonic anomaly substantially influences summer precipitation in China. Anomalous warming of tropical IO SST induces positive geopotential height anomalies in the subtropics and an east-west dipole pattern in midlatitudes over Asia. These anomalies also affect summer precipitation in China.

The combined effects of the ENSO and the Arctic Oscillation on the winter climate anomalies in East Asia

With the warm/cold phases of the El Niño and Southern Oscillation (ENSO) as a background, the impacts of monthly variation in the Arctic Oscillation (AO) on the winter climate anomalies in East Asia are studied with the NCEP/DOE Reanalysis 2 data and the Chinese station data regarding temperature and rainfall. The combined effects of ENSO and the AO indicate that the winter climate anomalies are mainly influenced by the AO in northern China and the ENSO in southern China, when an El Niño couples with a negative AO month or a La Niña couples with a positive AO month. These climate anomalies in China are consistent with the mechanisms proposed in previous studies. However, most of China presents a different pattern of climate anomalies if an El Niño couples with a positive AO month or a La Niña couples with a negative AO month, with the exception of the temperature anomalies in northern China, which are still affected dominantly by the AO. Further analysis suggests that the causes are attributed to the differences in both the stratosphere-troposphere interaction and the extratropics-tropics interaction. In the former cases, zonal symmetric circulation prevails in the winter and the extratropics-tropics interaction is weakened. Thus, the influences of the ENSO and the AO on the East Asian climate mainly present linear combination effects. On the contrary, an annular mode of atmospheric circulation is not favored in the latter cases and the extratropics-tropics interaction is strong. Hence, the combined effects of the ENSO and the AO on the winter climate in East Asia present nonlinear characteristics.

Earnings management and IPO anomalies in China

This paper empirically examines the impact of earnings management and investor sentiment on IPO anomalies using a sample of 506 Chinese IPOs issued over the 1998–2003 period. We develop a parsimonious pricing model in which both the offer price and the short-term aftermarket price are influenced by the use of earnings management, and show that the offer price can be below the fair price while the short-term equilibrium price in the aftermarket can be overvalued due to investor sentiment. Consistent with the overreaction hypothesis, the empirical results reveal a positive relation between the initial return and managed accruals and a negative relation between the long-term stock performance and the initial return. Earnings management appears to generate a pattern where the initial price following an IPO tends to be inflated by overreaction in the secondary market but adjusts to its fundamental level in the long run. These findings are robust across a variety of test specifications.

Spatio-temporal patterns of the area experiencing negative vegetation growth anomalies in China over the last three decades

Extreme climatic events like droughts, floods, heat waves and ice storms impact ecosystems as well as human societies. There is wide concern about how terrestrial ecosystems respond to extreme climatic events in the context of global warming. In this study, we used satellite-derived vegetation greenness data (Normalized Difference Vegetation Index; NDVI), in situ weather station data (temperature and precipitation) and the Palmer Drought Severity Index (PDSI) to analyze the spatio-temporal change of the area experiencing vegetation greenness anomalies and extreme climatic events in China from 1982 to 2009. At the national scale, we found that China experienced an increasing trend in heat waves and drought events during the study period. The average fraction of climate stations with drought events (defined by growing season PDSI <− 2) detected increased from 8% in the 1980s, to nearly 20% in the 2000s, at a rate of 0.6% yr−1 (R2 = 0.61, P < 0.001). In contrast, the area showing negative anomalies of vegetation greenness decreased at the rate of 0.9% yr−1 from 1982 to 2009 (R2 = 0.29, P = 0.003), although this trend stalled or reversed during the 2000s, particularly in northern China. The decrease in vegetation growth during the last decade over northern China was accompanied by the increase in extreme drought events in the 2000s. In southern China, although both precipitation and PDSI data suggest a greater area experiencing drought events during the 2000s than in the 1980s, the area showing negative vegetation greenness decreased consistently during the whole study period.

Variability study of ionospheric total electron content at crest of equatorial anomaly in China from 1997 to 2007

The variation of TEC data at Wuhan station (geographic coordinate: 30.5°N, 114.4°E; geomagnetic coordinate: 19.2°N, 183.8°E) at crest of equatorial anomaly in China from January 1997 to December 2007 were analyzed. Variability with solar activity, annual, semiannual, diurnal and seasonal variation were also analyzed. The MSIS00 model and ISR model were used to analyze the possible mechanisms of the variabilities found in the results. The TEC data in 1997 and 2001 deduced from another crest station Xiamen (geographic coordinate: 24.4°N, 118.1°E; geomagnetic coordinate: 13.2°N, 187.4°E) were used to contrast. Analysis results show that long-term variations of TEC at Xiamen station are mainly controlled by the variations of solar activities. Typical diurnal variation behaves as a minimum of the TEC in the pre-dawn hours around 05:00–06:00LT and a maximum on the afternoon hours around 13:00–15:00LT. Some features like the semiannual anomaly and winter anomaly in TEC have been reported. The anomaly may be the result of common action of the electric field over the magnetic equatorial and the [O/N2] at the crest station.

Variation of ionospheric total electron content at crest of equatorial anomaly in China from 1997 to 2004

The periodic variation of TEC data at Xiamen station (geographic coordinate: 24.4°N, 118.1°E; geomagnetic coordinate: 13.2°N, 187.4°E) at crest of equatorial anomaly in China from 1997 to 2004 is analyzed. The characteristic of TEC association with solar activity and geomagnetic activity are also analyzed. The method of continuous wavelet, cross wavelet and wavelet coherence transform methods have been used. Analysis results show that long-term variations of TEC at Xiamen station are mainly controlled by the variations of solar activities. Several remarkable components including 128–256 days, 256–512 days and 512–1024 days exist in TEC variations. The TEC data at Xiamen station is in anti-phase with geomagnetic Dst index in semiannual time-scale, but this response only exists during high solar activity. Diurnal variation of TEC is studied for different seasons. Some features like the semiannual anomaly and winter anomaly in TEC have been reported.

Integrated profiling of metabolites and trace elements reveals a multifaceted malnutrition in pregnant women from a region with a high prevalence of congenital malformations

Considerable evidence from epidemiological and clinical studies demonstrated that maternal nutritional status is closely associated with placental, embryonic, fetal growth and development, and ultimately pregnancy outcomes. In recent years, there has been a growing interest in the study of disorders of pregnancy using a metabolomic profiling approach. In this study, we presented an integrated comprehensive profiling approach to assess maternal nutritional status through measuring a wide variety of small-molecule metabolites and trace elements in serum of pregnant women. A total of 56 pregnant women with normal pregnancy outcomes were enrolled from Lvliang prefecture of Shanxi province, the area with the highest prevalence of congenital anomalies in China, and 40 pregnant women with normal pregnancies were recruited from Huairou county of Beijing city, the region representing a national average level. As compared with the national average level, these pregnant women from Lvliang region shown distinct metabolic phenotypic variations as revealed by the depleted serum concentrations of folate and vitamin B12, lower concentrations of carbohydrates, lipids, Se, Zn, and Cu, as well as higher concentrations of amino acids, urea-cycle metabolites, Sr, Cd, and Pb. Our results offer an improved understanding of severe multifaceted malnutrition in the pregnant women from a population with a high prevalence of congenital anomalies, highlighting the potential of a panel of critical nutrients as markers for aiding the diagnosis, prevention, and intervention of pregnancy complications.

Earnings Management and the Accrual Anomaly: Evidence from China

Using the unique Chinese setting in which the “delisting regulation” is based on accounting numbers, we separate earnings management into (1) earnings management responding to regulation and (2) earnings management prompted by market pressures and further document that earnings management responding to market pressures produces the accrual anomaly (Sloan, 1996) and earnings management responding to regulation does not. Initially unable to detect the accrual anomaly in China's stock market, we were reluctant to conclude that China's market is more efficient than that in the United States. After observing a disproportionate number of “big-bath” loss firm-years in the lowest decile of accruals for our sample, we estimated the apparent earnings distortion induced by the delisting regulation. When we excluded this distortion from our analysis, we documented the presence of the accrual anomaly in China's stock market. We conclude that the delisting regulation creates an artificial distribution of firm earnings in China that affects the market pricing of accruals and masks the accrual anomaly. The results have implications for policy makers and regulators in general, and those in emerging markets in particular.

Climate during the Medieval Climate Anomaly in China

Climate during the Medieval Climate Anomaly in China