scholarly journals Large-Scale Circulation Patterns Associated with Heavy Spring Rain Events over Taiwan in Strong ENSO and Non-ENSO Years

2003 ◽  
Vol 131 (8) ◽  
pp. 1769-1782 ◽  
Author(s):  
Zhihong Jiang ◽  
George Tai-Jen Chen ◽  
Ming-Chin Wu
Keyword(s):  
Coastal Area ◽  
Large Scale ◽  
Eastern China ◽  
Lower Troposphere ◽  
Heavy Rain ◽  
Interdecadal Variation ◽  
Frontal System ◽  
Rain Events ◽  
The Relationship ◽  
Strong Enso

Abstract Daily rainfall data at 15 stations in Taiwan and the grid dataset of the National Centers for Environmental Prediction–National Center for Atmospheric Research during the period of February–March 1951–2000 were used to reveal the characteristics of large-scale circulations associated with spring heavy rain events over Taiwan in strong ENSO and non-ENSO years. The effect of interdecadal variation on the relationship of spring rainfall and ENSO was also examined. Results showed that the different regimes of interdecadal variation that occurred in the late 1970s exert significant effect on the relationship between ENSO and spring rainfall in Taiwan. A pronounced positive correlation with statistical significance between cold season Niño-3 SST and the following spring rainfall over western Taiwan was only found since the late 1970s. Large-scale environmental conditions associated with the heavy spring rain events in strong ENSO and non-ENSO years were found to be quite different. Intrusion of a weak midlatitude frontal system into the eastern China coastal area coupled with an anomalous anticyclone over the Philippine Sea (PSAC) in the lower troposphere were primarily responsible for the spring heavy rain events in strong ENSO years. On the other hand, the intrusion of a much more intense midlatitude frontal system into China and the coastal area was necessary to generate spring heavy rain events in non-ENSO years. This difference is also instrumental for more frequent occurrence of heavy rainfall events and more rainfall amount observed in ENSO years.

scholarly journals Reply to “Comments on ‘Incorporating the Effects of Moisture into a Dynamical Parameter: Moist Vorticity and Moist Divergence’”

2016 ◽  
Vol 31 (4) ◽  
pp. 1397-1405
Author(s):  
Weihong Qian ◽  
Ning Jiang ◽  
Jun Du
Keyword(s):  
Large Scale ◽  
Value Added ◽  
Heavy Rain ◽  
Heavy Precipitation ◽  
Small Scale ◽  
Precipitation Efficiency ◽  
Long Duration ◽  
Advection Term ◽  
Rain Events ◽  
Mathematical Derivation

Abstract Mathematical derivation, meteorological justification, and comparison to model direct precipitation forecasts are the three main concerns recently raised by Schultz and Spengler about moist divergence (MD) and moist vorticity (MV), which were introduced in earlier work by Qian et al. That previous work demonstrated that MD (MV) can in principle be derived mathematically with a value-added empirical modification. MD (MV) has a solid meteorological basis. It combines ascent motion and high moisture: the two elements necessary for rainfall. However, precipitation efficiency is not considered in MD (MV). Given the omission of an advection term in the mathematical derivation and the lack of precipitation efficiency, MD (MV) might be suitable mainly for heavy rain events with large areal coverage and long duration caused by large-scale quasi-stationary weather systems, but not for local intense heavy rain events caused by small-scale convection. In addition, MD (MV) is not capable of describing precipitation intensity. MD (MV) worked reasonably well in predicting heavy rain locations from short to medium ranges as compared with the ECMWF model precipitation forecasts. MD (MV) was generally worse than (though sometimes similar to) the model heavy rain forecast at shorter ranges (about a week) but became comparable or even better at longer ranges (around 10 days). It should be reiterated that MD (MV) is not intended to be a primary tool for predicting heavy rain areas, especially in the short range, but is a useful parameter for calibrating model heavy precipitation forecasts, as stated in the original paper.

The 2010 Pakistan Flood and Russian Heat Wave: Teleconnection of Hydrometeorological Extremes

2012 ◽  
Vol 13 (1) ◽  
pp. 392-403 ◽  
Author(s):  
William K. M. Lau ◽  
Kyu-Myong Kim
Keyword(s):  
Heat Wave ◽  
Rossby Wave ◽  
Large Scale ◽  
Wave Train ◽  
Intraseasonal Oscillation ◽  
Heavy Rain ◽  
Atmospheric Blocking ◽  
Surface Energy Fluxes ◽  
Upper Level ◽  
Rain Events

Abstract In this paper, preliminary results are presented showing that the two record-setting extreme events during 2010 summer (i.e., the Russian heat wave–wildfires and Pakistan flood) were physically connected. It is found that the Russian heat wave was associated with the development of an extraordinarily strong and prolonged extratropical atmospheric blocking event in association with the excitation of a large-scale atmospheric Rossby wave train spanning western Russia, Kazakhstan, and the northwestern China–Tibetan Plateau region. The southward penetration of upper-level vorticity perturbations in the leading trough of the Rossby wave was instrumental in triggering anomalously heavy rain events over northern Pakistan and vicinity in mid- to late July. Also shown are evidences that the Russian heat wave was amplified by a positive feedback through changes in surface energy fluxes between the atmospheric blocking pattern and an underlying extensive land region with below-normal soil moisture. The Pakistan heavy rain events were amplified and sustained by strong anomalous southeasterly flow along the Himalayan foothills and abundant moisture transport from the Bay of Bengal in connection with the northward propagation of the monsoonal intraseasonal oscillation.

scholarly journals Orientasi Tata Kelola Perlindungan Dan Pemberdayaan Nelayan Kecil Di Provinsi Banten (Studi di Kabupaten Serang Dalam Masa Pandemi Covid 19)

2021 ◽  
Vol 7 (1) ◽  
pp. 360
Author(s):  
Mas Nana Jumena ◽  
Surya Anom
Keyword(s):  
Carrying Capacity ◽  
Coastal Area ◽  
Large Scale ◽  
Fish Resources ◽  
Fish Market ◽  
The People ◽  
Empirical Research Methods ◽  
Limited Supply ◽  
The Relationship ◽  
Responsible Manner

The relationship between fishermen and fisheries (sea) is very close, the dependence of fishermen on fish as a source of livelihood makes fish the main sector in coastal areas. Fish resources can be utilized for the greatest prosperity and welfare of the people, however the utilization of these fish resources must be carried out in a sustainable and responsible manner. This means that the utilization of fish resources must be carried out in a balanced manner and taking into account their carrying capacity and the ability of the resources to recover. During the current Covid 19 pandemic, fishermen's “fishing” activities in the Serang District of Banten Province have been disrupted, due to limited supply of fuel due to the PSBB (Large-Scale Social Restrictions), the catch is not selling well in the market or the reduced end (consumers) to the fish market . Indonesia since 2016 has had Law Number 7 of 2016 concerning the Protection and Empowerment of Fishermen, Fish Farmers and Salt Farmers, however the implementing regulations have not yet existed, so it is difficult to implement, moreover this regulation is urgently needed during a pandemic civid 19 this time.This writing is the result of an independent internal research that has been completed using legal (juridical) normative and empirical research methods (as supporting data and research arguments) carried out in the coastal area of Serang Regency.

scholarly journals Climate modulation of the Tibetan Plateau on haze in China

2016 ◽  
Vol 16 (3) ◽  
pp. 1365-1375 ◽  
Author(s):  
X. Xu ◽  
T. Zhao ◽  
F. Liu ◽  
S. L. Gong ◽  
D. Kristovich ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Large Scale ◽  
Climate Changes ◽  
Eastern China ◽  
Atmospheric Stability ◽  
Lower Troposphere ◽  
Pollutant Emissions ◽  
The Tibetan Plateau ◽  
Thermal Forcing ◽  
Haze Pollution

Abstract. Rapid increases in pollutant emissions in conjunction with stagnant meteorological conditions result in haze pollution in China. Recent frequent haze in China has attracted worldwide attention. Here we show a relationship between the haze events and Tibetan Plateau (TP)'s environment and climate changes. Based on observational data taken over recent decades, we identify central-eastern China (CEC) as a climatological large-scale “susceptible region” of frequent haze, which is harbored by the TP with its impact on midlatitude westerly winds. The observational and modeling studies demonstrate that the interannual variations in the thermal forcing of TP are positively correlated with the incidences of wintertime haze over CEC. Further analysis indicates that the climate warming of the TP induced changes in atmospheric circulation, driving frequent haze events in CEC. The frequent haze occurrences in CEC are consistent with decreasing winter monsoon winds, intensifying downward air flows and increasing atmospheric stability in the lower troposphere over the CEC in association with upstream plateau's thermal anomalies. Therefore, variations of haze in China are related to mechanical and thermal forcing by the TP. Our results also suggest that implications of the large TP topography for environment and climate changes should be taken into account for air pollution mitigation policies in China.

scholarly journals Impact of atmospheric circulations on aerosol distributions in autumn over eastern China: observational evidence

2015 ◽  
Vol 15 (21) ◽  
pp. 12115-12138 ◽  
Author(s):  
X. Y. Zheng ◽  
Y. F. Fu ◽  
Y. J. Yang ◽  
G. S. Liu
Keyword(s):  
Large Scale ◽  
Eastern China ◽  
Lower Troposphere ◽  
Reanalysis Data ◽  
Circulation Type ◽  
Lower Atmosphere ◽  
Study Region ◽  
Middle Troposphere ◽  
Heavy Pollution ◽  
Pollution Events

Abstract. Regional heavy pollution events in eastern China (110–122° E, 28–40° N) are causing serious environmental problems. In this study, the relationship between the degree of regional pollution and the patterns of large-scale atmospheric circulation over eastern China in October is investigated using 10-year (2001–2010) Terra/MODIS aerosol optical depth and NCEP reanalysis data by both case study and composite analysis. Eighteen polluted and 10 clean episodes are selected and categorised into six polluted types and three clean types respectively. Generally speaking, weather patterns such as a uniform surface pressure field in eastern China or a steady straight westerly in the middle troposphere, particularly when being at the rear of the anticyclone at 850 hPa, are typically responsible for heavy pollution events. Meanwhile, clean episodes occur when strong southeastward cold air advection prevails below the middle troposphere or air masses are transported from sea to land. Uniform descending motion prevails over the study region, trapping pollutants in the lower atmosphere. Therefore, the value of vertical velocity averaged from 1000 to 100 hPa and divergence of wind field in the lower troposphere are used in this study to quantify the diffusion conditions in each circulation type. The results reveal that it is often a clean episode when both the mean downward motion (larger than 2.56 × 10−2 Pa s−1) and the divergence of low-level winds (larger than 1.79 × 10−2 s−1) are strong. Otherwise, it is more likely to be a polluted episode.

scholarly journals Source-receptor relationships for airborne measurements of CO<sub>2</sub>, CO and O<sub>3</sub> above Siberia: a cluster-based approach

2010 ◽  
Vol 10 (4) ◽  
pp. 1671-1687 ◽  
Author(s):  
J.-D. Paris ◽  
A. Stohl ◽  
P. Ciais ◽  
P. Nédélec ◽  
B. D. Belan ◽  
...  
Keyword(s):  
Large Scale ◽  
Dispersion Model ◽  
Eastern China ◽  
Lower Troposphere ◽  
Particle Dispersion ◽  
Model Calculations ◽  
Air Masses ◽  
Airborne Measurements ◽  
Mixing Ratios ◽  
Source Regions

Abstract. We analysed results of three intensive aircraft campaigns above Siberia (April and September 2006, August 2007) with a total of ~70 h of continuous CO2, CO and O3 measurements. The flight route consists of consecutive ascents and descents between Novosibirsk (55° N, 82° E) and Yakutsk (62° N, 129° E). We performed retroplume calculations with the Lagrangian particle dispersion model FLEXPART for many short segments along the flight tracks. To reduce the extremely rich information on source regions provided by the model calculation into a small number of distinct cases, we performed a statistical clustering – to our knowledge for the first time – into potential source regions of the footprint emission sensitivities obtained from the model calculations. This technique not only worked well to separate source region influences but also resulted in clearly distinct tracer concentrations for the various clusters obtained. High CO and O3 concentrations were found associated with agricultural fire plumes originating from Kazakhstan in September 2006. A statistical analysis indicates that summer uptake of CO2 is largely explained (~50% of variance) by air mass exposure to uptake by Siberian and sub-arctic ecosystems. This resulted in an average 5 to 10 ppm difference with overlaying air masses. Stratosphere-troposphere exchange is found to strongly influence the observed O3 mixing ratios in spring, but not in summer. European emissions contributed to high O3 concentrations above Siberia in April 2006 and August 2007, while emissions from North Eastern China also contributed to higher O3 mixing ratios in summer, but tend to lower mixing ratios in spring, when the airmass aerosol burden is important. In the lower troposphere, large-scale deposition processes in the boreal and sub-arctic boundary layer is a large O3 sink, resulting in a ~20 ppb difference with overlaying air masses. Lagrangian footprint clustering is very promising and could also be advantageously applied to the interpretation of ground based measurements including calculation of tracers' sources and sinks.

scholarly journals Incorporating the Effects of Moisture into a Dynamical Parameter: Moist Vorticity and Moist Divergence

2015 ◽  
Vol 30 (6) ◽  
pp. 1411-1428 ◽  
Author(s):  
Weihong Qian ◽  
Jun Du ◽  
Xiaolong Shan ◽  
Ning Jiang
Keyword(s):  
Potential Vorticity ◽  
Eastern China ◽  
Heavy Rain ◽  
Systematic Evaluation ◽  
Rain Event ◽  
Dynamical Parameter ◽  
Rain Area ◽  
Moisture Effects ◽  
Moist Potential Vorticity ◽  
Rain Events

Abstract Properly including moisture effects into a dynamical parameter can significantly increase the parameter’s ability to diagnose heavy rain locations. The relative humidity–based weighting approach used to extend the moist potential vorticity (MPV) to the generalized moist potential vorticity (GMPV) is analyzed and demonstrates such an improvement. Following the same approach, two new diagnostic parameters, moist vorticity (MV) and moist divergence (MD), have been proposed in this study by incorporating moisture effects into the traditional vorticity and divergence. A regional heavy rain event that occurred along the Yangtze River on 1 July 1991 is used as a case study, and 41 daily regional heavy rain events during the notorious flooding year of 1998 in eastern China are used for a systematic evaluation. Results show that after the moisture effects were properly incorporated, the improved ability of all three parameters to capture a heavy rain area is significant (statistically at the 99% confidence level): the GMPV is improved over the MPV by 194%, the MD over the divergence by 60%, and the MV over the vorticity by 34% in terms of the threat score (TS). The average TS is 0.270 for the MD, 0.262 for the MV, and 0.188 for the GMPV. Application of the MV and MD to assess heavy rain potential is not intended to replace a complete, multiscale forecasting methodology; however, the results from this study suggest that the MV and MD could be used to postprocess a model forecast to potentially improve heavy rain location predictions.

Seawater intrusion and aquifer freshening near reclaimed coastal area of Shenzhen

2007 ◽  
Vol 7 (2) ◽  
pp. 137-145 ◽  
Author(s):  
K.P. Chen ◽  
J.J. Jiao
Keyword(s):  
Seawater Intrusion ◽  
Coastal Area ◽  
Large Scale ◽  
Land Reclamation ◽  
Groundwater Pumping ◽  
Fresh Groundwater ◽  
Saline Groundwater ◽  
Aquifer System ◽  
Large Scale Land ◽  
The Relationship

Local groundwater in coastal aquifers in Shenzhen has experienced heavy pumping since the 1980s when it began to expand very quickly from a fishing village to a modern city. Meanwhile, large-scale land reclamation was carried out to meet the needs of various urbanization projects. In this paper we analyzed the groundwater from a coastal aquifer system in Shenzhen and examined the evolution of groundwater chemistry over the last 20 years. The temporal changes of ionic ratios of rCa/(rHCO3 + rSO4) and the relationship between sodium and chloride in the coastal area over this period indicate that the aquifer experienced seawater intrusion in the 1980s but underwent gradual freshening in the 1990s. It is speculated that seawater intrusion was induced by excessive groundwater pumping and that the aquifer freshening was caused both by the recent reduction in groundwater pumping and by coastal reclamation which moved the interface between fresh groundwater and saline groundwater seaward.

scholarly journals Climate modulation of the Tibetan Plateau on haze in China

2015 ◽  
Vol 15 (20) ◽  
pp. 28915-28937 ◽  
Author(s):  
X. Xu ◽  
T. Zhao ◽  
F. Liu ◽  
S. L. Gong ◽  
D. Kristovich ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Large Scale ◽  
Climate Changes ◽  
Eastern China ◽  
Atmospheric Stability ◽  
Lower Troposphere ◽  
Pollutant Emissions ◽  
The Tibetan Plateau ◽  
Thermal Forcing ◽  
Haze Pollution

Abstract. Rapid increases in pollutant emissions in conjunction with stagnant meteorological conditions result in haze pollution in China. Recent frequent haze in China has attracted worldwide attention. Here we show a relationship between the haze events and Tibetan Plateau (TP)'s environment and climate changes. Based on observational data taken over recent decades, we identify central-eastern China (CEC) as a climatological large-scale "susceptible region" of frequent haze, which is harbored by the TP with its impact on mid-latitude westerly winds. The observational and modeling studies demonstrate that the interannual variations in the thermal forcing of TP are positively correlated with the incidences of wintertime haze over CEC. Further analysis indicates that the TP-climate warming induced changes in atmospheric circulation driving frequent haze events in CEC. The frequent haze occurrences in CEC are consistent with decreasing winter monsoon winds, intensifying downward air flows and increasing atmospheric stability in the lower troposphere over the CEC in association with upstream plateau's thermal anomalies. Therefore, variations of haze in China are related to mechanical and thermal forcing by the TP. Our results also suggest that implications of the large TP-topography for environment and climate changes should be taken into account for air pollution mitigation policies in China.

scholarly journals Spring Heavy Rain Events in Taiwan during Warm Episodes and the Associated Large-Scale Conditions

2003 ◽  
Vol 131 (7) ◽  
pp. 1173-1188 ◽  
Author(s):  
George Tai-Jen Chen ◽  
Zhihong Jiang ◽  
Ming-Chin Wu
Keyword(s):  
Large Scale ◽  
Heavy Rain ◽  
Rain Events
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