scholarly journals Insights from a joint analysis of Indian and Chinese monsoon rainfall data

2011 ◽  
Vol 15 (8) ◽  
pp. 2709-2715 ◽  
Author(s):  
M. Zhou ◽  
F. Tian ◽  
U. Lall ◽  
H. Hu
Keyword(s):  
Large Scale ◽  
Monsoon Rainfall ◽  
Indian Monsoon ◽  
Southern China ◽  
Principal Component ◽  
Northern China ◽  
Rainfall Data ◽  
Joint Analysis ◽  
Climate Indices ◽  
The Common

Abstract. Monsoon rainfall is of great importance for agricultural production in both China and India. Understanding the features of the Indian and Chinese monsoon rainfall and its long term predictability is a challenge for research. In this paper Principal Component Analysis (PCA) method was adopted to analyze Indian monsoon and Chinese monsoon separately as well as jointly during the period 1951 to 2003. The common structure of Indian monsoon and Chinese monsoon rainfall data was explored, and its correlation with large scale climate indices and thus the possibility of prediction were analyzed. The joint PCA results gives a clearer correlation map between Chinese monsoon rainfall and Indian monsoon rainfall. The common rainfall structure presents a significant teleconnection to Sea Surface Temperature anomaly (SSTa), moisture transport and other climate indices. Specifically, our result shows that Northern China would garner less rainfall when whole Indian rainfall is below normal, and with cold SSTa over the Indonesia region more rainfall would be distributed over India and Southern China. The result also shows that SSTa in the previous winter months could be a good indicator for the summer monsoon rainfall in China.

scholarly journals Insights from a joint analysis of Indian and Chinese monsoon rainfall data

2011 ◽  
Vol 8 (2) ◽  
pp. 3167-3187 ◽  
Author(s):  
M. Zhou ◽  
F. Tian ◽  
U. Lall ◽  
H. Hu
Keyword(s):  
Agricultural Production ◽  
Monsoon Rainfall ◽  
Temperature Anomaly ◽  
Northern China ◽  
Joint Analysis ◽  
Climate Indices ◽  
Sea Surface Temperature Anomaly ◽  
Indian Rainfall ◽  
Long Term Prediction

Abstract. Monsoon rainfall is of great importance for the agricultural production in both China and India. Understanding its rule and possibility of long term prediction is a challenge for research. This paper gives a joint analysis of Indian monsoon and Chinese monsoon, finds their teleconnection to Sea Surface Temperature anomaly (SSTa) and other climate indices individually and relationship in common. The results show that northern China garners less rainfall when whole Indian rainfall is below normal. Also, with cold SSTa over the Indonesia region, more rainfall would be distributed over India and South China.

scholarly journals A Hydroclimatological Analysis of Precipitation in the Ganges–Brahmaputra–Meghna River Basin

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1359 ◽  
Author(s):  
Scott Curtis ◽  
Thomas Crawford ◽  
Munshi Rahman ◽  
Bimal Paul ◽  
M. Miah ◽  
...  
Keyword(s):  
Interannual Variability ◽  
River Basin ◽  
Significant Relationship ◽  
Large Scale ◽  
Monsoon Rainfall ◽  
Southern Oscillation ◽  
Wave Train ◽  
Principal Component ◽  
South Atlantic ◽  
The Ganges

Understanding seasonal precipitation input into river basins is important for linking large-scale climate drivers with societal water resources and the occurrence of hydrologic hazards such as floods and riverbank erosion. Using satellite data at 0.25-degree resolution, spatial patterns of monsoon (June-July-August-September) precipitation variability between 1983 and 2015 within the Ganges–Brahmaputra–Meghna (GBM) river basin are analyzed with Principal Component (PC) analysis and the first three modes (PC1, PC2 and PC3) are related to global atmospheric-oceanic fields. PC1 explains 88.7% of the variance in monsoonal precipitation and resembles climatology with the center of action over Bangladesh. The eigenvector coefficients show a downward trend consistent with studies reporting a recent decline in monsoon rainfall, but little interannual variability. PC2 explains 2.9% of the variance and shows rainfall maxima to the far western and eastern portions of the basin. PC2 has an apparent decadal cycle and surface and upper-air atmospheric height fields suggest the pattern could be forced by tropical South Atlantic heating and a Rossby wave train stemming from the North Atlantic, consistent with previous studies. Finally, PC3 explains 1.5% of the variance and has high spatial variability. The distribution of precipitation is somewhat zonal, with highest values at the southern border and at the Himalayan ridge. There is strong interannual variability associated with PC3, related to the El Nino/Southern Oscillation (ENSO). Next, we perform a hydroclimatological downscaling, as precipitation attributed to the three PCs was averaged over the Pfafstetter level-04 sub-basins obtained from the World Wildlife Fund (Gland, Switzerland). While PC1 was the principal contributor of rainfall for all sub-basins, PC2 contributed the most to rainfall in the western Ganges sub-basin (4524) and PC3 contributed the most to the rainfall in the northern Brahmaputra (4529). Monsoon rainfall within these two sub-basins were the only ones to show a significant relationship (negative) with ENSO, whereas four of the eight sub-basins had a significant relationship (positive) with sea surface temperature (SST) anomalies in the tropical South Atlantic. This work demonstrates a geographic dependence on climate teleconnections in the GBM that deserves further study.

scholarly journals Contrasting Performance of the Remotely-Derived GPP Products over Different Climate Zones across China

2019 ◽  
Vol 11 (16) ◽  
pp. 1855 ◽  
Author(s):  
Yanan Chen ◽  
Hongfan Gu ◽  
Munan Wang ◽  
Qing Gu ◽  
Zhi Ding ◽  
...  
Keyword(s):  
Large Scale ◽  
Climatic Factors ◽  
Southern China ◽  
Gross Primary Production ◽  
Terrestrial Ecosystems ◽  
Northern China ◽  
Tibet Plateau ◽  
Semiarid Region ◽  
Interannual Variations ◽  
Climate Zones

Precise quantification of terrestrial gross primary production (GPP) has been recognized as one of the most important components in understanding the carbon balance between the biosphere and the atmosphere. In recent years, although many large-scale GPP estimates from satellite data and ecosystem models have been generated, few attempts have been made to compare the different GPP products at national scales, particularly for various climate zones. In this study, two of the most widely-used GPP datasets were systematically compared over the eight climate zones across China’s terrestrial ecosystems from 2001 to 2015, which included the moderate resolution imaging spectroradiometer (MODIS) GPP and the breathing Earth system simulator (BESS) GPP products. Additionally, the coarse (0.05o) GPP estimates from the vegetation photosynthesis model (VPM) at the same time scale were used for auxiliary analysis with the two products. Both MODIS and BESS products exhibited a decreasing trend from the southeast region to the northwest inland. The largest GPP was found in the tropical humid region with 5.49 g C m−2 d−1 and 5.07 g C m−2 d−1 for MODIS and BESS, respectively, while the lowest GPP was distributed in the warm temperate arid region, midtemperate semiarid region and plateau zone. Meanwhile, the work confirmed that all these GPP products showed apparent seasonality with the peaks in the summertime. However, large differences were found in the interannual variations across the three GPP products over different climate regions. Generally, the BESS GPP agreed better than the MODIS GPP when compared to the seasonal and interannual variations of VPM GPP. Furthermore, the spatial correlation analysis between terrestrial GPP and the climatic factors, including temperature and precipitation, indicated that natural rainfall dominated the variability in GPP of Northern China, such as the midtemperate semiarid region, while temperature was a key controlling factor in the Southern China and the Tibet Plateau area.

scholarly journals A Case Study of Subtropical Frontogenesis during a Blocking Event

2007 ◽  
Vol 135 (7) ◽  
pp. 2588-2609 ◽  
Author(s):  
George Tai-Jen Chen ◽  
Chung-Chieh Wang ◽  
An-Hsiang Wang
Keyword(s):  
Large Scale ◽  
Frontal Zone ◽  
Southern China ◽  
Sensible Heat Flux ◽  
Northern China ◽  
Sensible Heat ◽  
Surface Data ◽  
Sea Area ◽  
Blocking Event

Abstract During 8–14 June 2000, a 500-hPa blocking event occurred over Mongolia and northern China (near 45°N, 108°E), which was the only case over this region in June since 1981. As the block developed, the initially weak low-level mei-yu front over southern China evolved into a system with strong baroclinity and subsequently moved south. The frontal passage over Taiwan caused temperatures to drop by 10°C, the largest in June over two decades. Using gridded analyses, manually analyzed weather maps, and satellite and surface data, the present study investigates the evolution of this mei-yu front under the influence of the block. The 925-hPa frontogenetical function is computed and effects of different processes are discussed. As the blocking event developed, concurrent ridge–trough amplification in the lower–midtroposphere produced a reversed thermal pattern. The lower-tropospheric high moved southward, and large-scale confluence and deformation were enhanced between the northerly flow and the prefrontal southwesterly flow. The location of the block, to the west-southwest of the Okhotsk Sea area, allowed it to affect the front over southern China and caused it to penetrate inside 20°N, unusual for the month of June. The distribution of the frontogenetical function indicated that the mei-yu frontogenesis and the maintenance of the front were attributed to both deformation and convergence. These two processes together counteracted the strong frontolysis along the frontal zone from diabatic effects, caused by evaporative cooling of frontal precipitation on the warm side and stronger sensible heat transfer (and daytime heating over less cloudy areas) on the cold side of the front. When deformation, convergence, and diabatic effects were all combined, the net total frontogenesis peaked slightly ahead of the frontal zone, thus contributing to the southward propagation of the front in addition to the advection by postfrontal cold air in the present case. When the front moved into the South China Sea, the cross-frontal thermal gradient diminished rapidly, mainly due to the frontolytic effect from sensible heat flux over warm waters.

scholarly journals Contamination With Fumonisin B and Deoxynivalenol Is a Threat to Egg Safety and Contributes to Gizzard Ulcerations of Newborn Chickens

2021 ◽  
Vol 12 ◽  
Author(s):  
Yihui Wang ◽  
Hongkun Quan ◽  
Xiaohui Li ◽  
Qiang Li ◽  
Md Atiqul Haque ◽  
...  
Keyword(s):  
Large Scale ◽  
Southern China ◽  
Northern China ◽  
Poultry Feed ◽  
Hatching Rate ◽  
Post Inoculation ◽  
Poultry Industry ◽  
Average Residual ◽  
Poultry Diets ◽  
Aflatoxin B

Fumonisin B (FB) and other fumonisins, deoxynivalenol (DON), and zearalenone (ZEN) are mycotoxins (secondary metabolites of fungi) present at high levels of contamination in poultry diets and threatening the sustainability of the poultry industry and egg safety for consumers. However, residual mycotoxins in breeder eggs and their effects on chicken progeny and gizzard ulcerations remain unclear. To unveil mycotoxin contaminations from daily diets to breeder eggs, 293 poultry feed samples were collected from three large-scale poultry provinces across Northern China to Southern China. Average levels of 1,628 ± 4.36 μg/kg of FB1, 593 ± 11.16 μg/kg of DON, 69 ± 9.21 μg/kg of ZEN, 52 ± 7.33 μg/kg of OTA, and 24 ± 5.85 μg/kg of AFB1 were found in feedstuffs and poultry diets using commercial ELISA kits. In terms of residual mycotoxins in breeder eggs, FB1 and DON contaminations dominated residues in egg albumen and yolk samples. Out of 221 breeder eggs, the average residual of FB1 in albumen were 320.6 ± 10.12 μg/kg (Hebei), 420.2 ± 10.98 μg/kg (Guangdong), and 549.4 ± 10.27 (Guangxi). Moreover, higher residual of DONs were determined in Guangdong and Guangxi provinces compared to Hebei province. ZEN, ochratoxins A (OTA), and aflatoxin B1 (AFB1) contamination at low levels were found in the above samples collected from afronmentioned three provinces. Based on residual mycotoxins in breeder eggs, SPF embryonated eggs aged 11 days were inoculated into albumen with different doses of FB1, FB2 or DON, or a combination of FB1 and DON, or a combination of FB1 with FB2 and FB3. A lower hatching rate was observed in the chicken progenies with the combination of 24 μg of FB1 and 0.1 μg of DON compared to other treatments. Moreover, typical gizzard ulcerations with hemorrhagic lungs were observed in the progeny of breeder eggs post-inoculation of 24 μg of FB1 and synergetic inoculation of FB1 and DON. Finally, residual FB mycotoxins were detected in the gizzards and in the lungs of the progenies. Based on the above evidence, feed-borne FB1 and DON are dominant mycotoxins in breeder eggs and threatening food security using breeder eggs as a Trojan horse. More importantly, the residual of FB1 alone and in combination with of DON contamination are associated with low hatching rate and gizzard ulcerations in chicken progenies, hampering sustainable development perspectives of the poultry industry.

scholarly journals Fractal-Based Modeling and Spatial Analysis of Urban Form and Growth: A Case Study of Shenzhen in China

2020 ◽  
Vol 9 (11) ◽  
pp. 672
Author(s):  
Xiaoming Man ◽  
Yanguang Chen
Keyword(s):  
Fractal Dimension ◽  
Urban Growth ◽  
Urban Form ◽  
Fractal Structure ◽  
Southern China ◽  
Growth Curves ◽  
Northern China ◽  
Logistic Function ◽  
Urban Region ◽  
The Common

Fractal dimension curves of urban growth can be modeled with sigmoid functions, including logistic function and quadratic logistic function. Different types of logistic functions indicate different spatial dynamics. The fractal dimension curves of urban growth in Western countries follow the common logistic function, while the fractal dimension growth curves of cities in northern China follow the quadratic logistic function. Now, we want to investigate whether other Chinese cities, especially cities in South China, follow the same rules of urban evolution and attempt to analyze the reasons. This paper is devoted to exploring the fractals and fractal dimension properties of the city of Shenzhen in southern China. The urban region is divided into four subareas using ArcGIS technology, the box-counting method is adopted to extract spatial datasets, and the least squares regression method is employed to estimate fractal parameters. The results show that (1) the urban form of Shenzhen city has a clear fractal structure, but fractal dimension values of different subareas are different; (2) the fractal dimension growth curves of all the four study areas can only be modeled by the common logistic function, and the goodness of fit increases over time; (3) the peak of urban growth in Shenzhen had passed before 1986 and the fractal dimension growth is approaching its maximum capacity. It can be concluded that the urban form of Shenzhen bears characteristics of multifractals and the fractal structure has been becoming better, gradually, through self-organization, but its land resources are reaching the limits of growth. The fractal dimension curves of Shenzhen’s urban growth are similar to those of European and American cities but differ from those of cities in northern China. This suggests that there are subtle different dynamic mechanisms of city development between northern and southern China.

Atlantic Zonal Mode-Monsoon teleconnection in CMIP6 Models

2020 ◽  
Author(s):  
Sabeerali Cherumadanakadan Thelliyil ◽  
Ravindran Ajayamohan ◽  
Praveen Veluthedathekuzhiyil
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Monsoon Rainfall ◽  
Indian Summer Monsoon Rainfall ◽  
Central India ◽  
Seasonal Prediction ◽  
Underlying Mechanism ◽  
Summer Monsoon Rainfall ◽  
Coupled Models ◽  
The Common

<p>Atlantic Zonal Mode (AZM) and Indian summer monsoon rainfall (ISMR) are known to have an inverse relationship, which means that the cold (warm) phases of AZM result in strong (weak) ISMR. The realistic simulation of AZM and its teleconnection with ISMR in coupled models is important for the better seasonal prediction of ISMR. Here, we evaluated the performance of 26 CMIP6 models in simulating the AZM-ISMR teleconnection using 40 years of historical simulations. The skill of most CMIP6 models in simulating the teleconnection between AZM and ISMR is poor. Out of the 26 models analyzed, only 10 models show the correct sign of AZM related rainfall response over central India. The underlying mechanism responsible for the models' failure in capturing AZM-teleconnection is studied using the large-scale dynamical/thermodynamical variables. By choosing a set of good and bad models we unravel the common biases responsible for the wrong teleconnection between AZM-ISMR. This study highlights the importance of correcting AZM‐ISMR teleconnection in climate models for better seasonal monsoon prediction.</p>

scholarly journals Regression-based season-ahead drought prediction for southern Peru conditioned on large-scale climate variables

2017 ◽  
Author(s):  
Eric Mortensen ◽  
Shu Wu ◽  
Michael Notaro ◽  
Steven Vavrus ◽  
Rob Montgomery ◽  
...  
Keyword(s):  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Local Level ◽  
Principal Component ◽  
Spatiotemporal Variability ◽  
Climate Indices ◽  
Southern Peru ◽  
Drought Prediction

Abstract. Located at a complex topographic, climatic, and hydrologic crossroads, southern Peru is a semi-arid region that exhibits high spatiotemporal variability in precipitation. The economic viability of the region hinges on this water, yet southern Peru is prone to water scarcity caused by seasonal drought. Droughts here are often triggered during El Niño episodes; however, other large-scale climate mechanisms also play a noteworthy role in controlling the region’s hydrologic cycle. An extensive season-ahead drought prediction model is developed to help bolster existing capacity of stakeholders to plan for and mitigate the deleterious impacts of this hydrologic extreme. In addition to existing climate indices, large-scale climatic variables, such as sea surface temperature, are investigated to identify potential drought predictors. A principal component regression framework is applied to eleven potential predictors to produce an ensemble forecast of January-March precipitation. Model hindcasts of 51 years, compared to climatology and another model conditioned solely on an El Niño-Southern Oscillation index, achieve notable skill and perform better for several metrics, including ranked probability skill score and a hit-miss statistic. Extending the lead time and spatially disaggregating precipitation predictions to the local level may further assist regional stakeholders and policymakers preparing for drought.

Dynamics of East Asian Spring Rainband and spring-autumn contrast: Environmental forcings of large-scale circulation

2021 ◽  
pp. 1-59
Author(s):  
Shi-Xin Wang ◽  
Hong-Chao Zuo ◽  
Fen Sun ◽  
Li-Yang Wu ◽  
Yixing Yin ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Large Scale ◽  
Southern China ◽  
East Asian ◽  
Baroclinic Instability ◽  
Northern China ◽  
Reanalysis Dataset ◽  
Warm Advection ◽  
Westerly Jet ◽  
External Forcings

AbstractDynamics of the East Asian spring rainband are investigated with reanalysis dataset and station observations. Here, it is revealed that the rainband is anchored by external forcings. Midtropospheric jet core stays quasi-stationary around Japan. It has two branches in its entry region, which originate from the south and north flanks of Tibetan Plateau and then run northeastward and southeastward, respectively. The southern branch advects warm air from the Hengduan-Tibetan plateaus northeastwards, forming rainband over southern China through both causing adiabatic ascent motion and triggering diabatic feedback. The rainband is much stronger in spring than in autumn due to the stronger diabatic heating over Hengduan-Tibetan Plateau, more southward-displaced midtropospheric jet and resultant stronger warm advection over southern China. The northern jet branch forms a zonally-elongated cold advection belt, which reaches the maximum around northern China, and then weakens and extends eastwards towards east of Japan. The westerly jet also steers strong disturbance activities roughly collocated with the cold advection belt via baroclinic instability. The high disturbance activities belt causes large cumulative warm advections (CWA) through drastically increasing extremely warm-advection days in its eastern and south flank, where weak cold advection prevails. CWA is more essential for monthly/seasonally rainfall than conventionally-used time-average temperature advection because it is revealed that strengthened warm advection can increase rainfall through positive diabatic feedback, while cold advection cannot cause negative rainfall. Thus, the rainband is collocated with the large CWA belt instead of the 48 warm advection south of it. This rainband is jointed to the rainband over southern China, forming the long southwest-northeast-oriented East Asian spring rainband. Southeastward-increasing moisture slightly displaces the rainband southeastwards.

scholarly journals Linkages between Large-Scale Climate Patterns and Karst Spring Discharge in Northern China

2016 ◽  
Vol 17 (2) ◽  
pp. 713-724 ◽  
Author(s):  
Xueli Huo ◽  
Zhongfang Liu ◽  
Qingyun Duan ◽  
Pengmei Hao ◽  
Yanyan Zhang ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Time Scales ◽  
Large Scale ◽  
Southern Oscillation ◽  
Northern China ◽  
Climate Indices ◽  
Spring Discharge ◽  
Climate Conditions ◽  
Climate Patterns ◽  
Periodic Components

Abstract The Niangziguan Springs (NS) discharge is used as a proxy indicator of the variability of the karst groundwater system in relation to major climate indices such as El Niño–Southern Oscillation (ENSO), Pacific decadal oscillation (PDO), Indian summer monsoon (ISM), and west North Pacific monsoon (WNPM). The relationships between spring discharge and these climate indices are determined using the multitaper method (MTM), continuous wavelet transform (CWT), and wavelet transform coherence (WTC). Significant periodic components of spring discharge in the 1-, 3.4-, and 26.8-yr periodicities are identified and reconstructed for further investigation of the correlation between spring discharge and large-scale climate patterns on these time scales. Correlation coefficients and WTC between spring discharge and the climate indices indicate that variability in spring discharge is significantly and positively correlated with monsoon indices in the 1-yr periodicity and negatively correlated with ENSO in the 3.4-yr periodicity and PDO in the 26.8-yr periodicity. This suggests that the oscillations of the spring discharge on annual, interannual, and interdecadal time scales are dominated by monsoon, ENSO, and PDO in the NS basin, respectively. Results show that monsoons modulate the spring discharge by affecting local meteorological parameters. ENSO and PDO impact the variability of the NS discharge by affecting the climate conditions in northern China.

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