scholarly journals Pollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines

2010 ◽  
Vol 10 (4) ◽  
pp. 1649-1660 ◽  
Author(s):  
S. C. Lai ◽  
A. K. Baker ◽  
T. J. Schuck ◽  
P. van Velthoven ◽  
D. E. Oram ◽  
...  
Keyword(s):  
South China ◽  
Source Region ◽  
Sampling Period ◽  
The Philippines ◽  
Substantial Contribution ◽  
Back Trajectory ◽  
Upper Troposphere ◽  
Chemical Tracers ◽  
Back Trajectory Analysis ◽  
Pollution Events

Abstract. A strong pollution episode in the upper troposphere between South China and the Philippines was observed during CARIBIC flights in April 2007. Five pollution events were observed, where enhancements in aerosol and trace gas concentrations including CO, CO2, CH4, non-methane hydrocarbons (NMHCs) and halocarbons were observed along the flight tracks during four sequential flights. The importance of the contribution of biomass/biofuel burning was investigated using chemical tracers, emission factor analysis, back-trajectory analysis and satellite images. The Indochinese peninsula was identified as the probable source region of biomass/biofuel burning. However, enhancements in the urban/industrial tracer C2Cl4 during the events also indicate a substantial contribution from urban anthropogenic emissions. An estimation of the contribution of fossil fuel versus biomass/biofuel to the CO enhancement was made, indicating a biomass/biofuel burning contribution of ~54 to ~92% of the observed CO enhancements. Biomass/biofuel burning was found to be the most important source category during the sampling period.

scholarly journals Pollution plumes observed during CARIBIC flights in the upper troposphere between South China and the Philippines

2009 ◽  
Vol 9 (5) ◽  
pp. 21891-21913
Author(s):  
S. C. Lai ◽  
A. K. Baker ◽  
T. J. Schuck ◽  
P. van Velthoven ◽  
D. E. Oram ◽  
...  
Keyword(s):  
South China ◽  
Source Region ◽  
The Philippines ◽  
Substantial Contribution ◽  
Back Trajectory ◽  
Upper Troposphere ◽  
Chemical Tracers ◽  
Back Trajectory Analysis ◽  
Anthropogenic Component ◽  
Pollution Plumes

Abstract. A strong pollution episode in the upper troposphere between South China and the Philippines was observed during CARIBIC flights in April 2007. Five pollution plumes were intersected and enhancements in aerosol and trace gas concentrations including CO, CO2, CH4, non-methane hydrocarbons (NMHCs) and halocarbons were observed along the flight tracks during four sequential flights. The importance of the contribution of biomass burning was investigated using chemical tracers, emission factor analysis, back-trajectory analysis and satellite images. The Indochinese peninsula was identified as the probable source region of biomass/biofuel burning. However, enhancements in the urban/industrial tracer C2Cl4 in the plumes also indicate a substantial contribution from anthropogenic emissions. An estimation of the anthropogenic component of CO shows that biomass/biofuel burning contributed 44–63% to the intersected plumes.

scholarly journals Analysis of ΔO<sub>2</sub>/ΔCO<sub>2</sub> ratios for the pollution events observed at Hateruma Island, Japan

2012 ◽  
Vol 12 (5) ◽  
pp. 2713-2723 ◽  
Author(s):  
C. Minejima ◽  
M. Kubo ◽  
Y. Tohjima ◽  
H. Yamagishi ◽  
Y. Koyama ◽  
...  
Keyword(s):  
Particle Dispersion ◽  
Back Trajectory ◽  
Cement Production ◽  
Mixing Ratios ◽  
Back Trajectory Analysis ◽  
Fossil Fuel Burning ◽  
Significant Difference ◽  
Pollution Events ◽  
Good Agreement

Abstract. Pollution events extracted from the in situ observations of atmospheric CO2 and O2 mixing ratios at Hateruma Island (HAT, 24° N, 124° E) during the period from October 2006 and December 2008 are examined. The air mass origins for the pollution events are categorized by using back trajectory analysis, and the oxidative ratios (OR = −O2:CO2 molar exchange ratio) for selected pollution events are calculated. We find that there is a significant difference in the average oxidative ratios between events from China (OR = 1.14 ± 0.12, n = 25) and Japan/Korea (OR = 1.37 ± 0.15, n = 16). These values are in a good agreement with the national average oxidative ratios for the emissions from fossil fuel burning and cement production (FFBC) in China (ORFFBC = 1.11 ± 0.03) and Korea/Japan (ORFFBC = 1.36 ± 0.02). Compared with the observation, simulations of the atmospheric O2 and CO2 mixing ratios using Lagrangian particle dispersion models do a good job in reconstructing the average oxidative ratio of the pollution events originating in China but tend to underestimate for events originating in Japan/Korea. A sensitivity test suggests that the simulated atmospheric oxidative ratios at HAT are especially sensitive to changes in Chinese fuel mix.

Seeking Accountability, Legitimacy, and Transparency: Congressional Intervention in the Philippines’ South China Sea Policy

2020 ◽  
Vol 41 (1-2) ◽  
pp. 161-191
Author(s):  
Robert Joseph Medillo
Keyword(s):  
Foreign Policy ◽  
South China Sea ◽  
South China ◽  
Domestic Politics ◽  
The Philippines ◽  
Comparative Case Study ◽  
Congressional Hearings ◽  
China Sea ◽  
News Reports ◽  
Government Documents

Abstract Why and how did the Philippine Congress intervene in the policies of Arroyo (hedging), Aquino III (balancing), and Duterte (appeasement) on the South China Sea disputes? In particular, why and how did the Philippine Congress challenge each president’s attempt to forge either cooperation or confrontation towards China? Guided by the domestic politics – foreign policy nexus, this article explores the dynamic role of the Philippine Congress in the country’s foreign policy process. It combines comparative case-study and content analysis methods to examine relevant congressional records, government documents, public speeches, and news reports. This article finds that the impetus behind Congress’ intervention was to seek accountability, legitimacy, and transparency via registering a bill or passing a law, filing legislative resolutions, holding congressional hearings, calling for impeachment proceedings, delivering privilege speeches, and issuing press releases. This article offers its empirical and theoretical contributions to broaden current understanding of the relationship between domestic politics and foreign policy.

The South China Sea Arbitration: Bindingness, Finality, and Compliance with UNCLOS Dispute Settlement Decisions

2017 ◽  
Vol 8 (1) ◽  
pp. 36-50
Author(s):  
Hao Duy PHAN ◽  
Lan Ngoc NGUYEN
Keyword(s):  
South China Sea ◽  
South China ◽  
Dispute Settlement ◽  
The Philippines ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Binding Force ◽  
State Compliance ◽  
Dispute Settlement Mechanisms

AbstractOn 12 July 2016, the Tribunal in theSouth China Seaarbitration issued its final award. China rejected the ruling as “null and void”. The Philippines dismissed it as “a piece of paper” after initially hailing the ruling a “milestone decision”. The reactions of the parties concerned raise important questions about the bindingness, finality, and state compliance with UNCLOS dispute settlement decisions. This paper addresses these questions by dissecting China’s arguments that the award “has no binding force” and by examining the options available for promoting compliance with the award. The paper also considers the broader question of how states generally comply with UNCLOS dispute settlement decisions and evaluates the significance of UNCLOS dispute settlement mechanisms, including theSouth China Seaarbitration, in the absence of external enforcement.

scholarly journals Use of Low-Cost Ambient Particulate Sensors in Nablus, Palestine with Application to the Assessment of Regional Dust Storms

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 539
Author(s):  
Abdelhaleem Khader ◽  
Randal S. Martin
Keyword(s):  
Low Cost ◽  
Dust Storms ◽  
Air Pollutant ◽  
World Health ◽  
Back Trajectory ◽  
Hysplit Model ◽  
Air Masses ◽  
Palestinian Territories ◽  
Back Trajectory Analysis ◽  
Lower Elevation

Few air pollutant studies within the Palestinian territories have been reported in the literature. In March–April and May–June of 2018, three low-cost, locally calibrated particulate monitors (AirU’s) were deployed at different elevations and source areas throughout the city of Nablus in Northern West Bank, Palestine. During each of the three-week periods, high but site-to-site similar particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5) and less than 10 µm (PM10) concentrations were observed. The PM2.5 concentrations at the three sampling locations and during both sampling periods averaged 38.2 ± 3.6 µg/m3, well above the World Health Organization’s (WHO) 24 h guidelines. Likewise, the PM10 concentrations exceeded or were just below the WHO’s 24 h guidelines, averaging 48.5 ± 4.3 µg/m3. During both periods, short episodes were identified in which the particulate levels at all three sites increased substantially (≈2×) above the regional baseline. Air mass back trajectory analyses using U.S. National Oceanic and Atmospheric Administration’s (NOAA) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggested that, during these peak episodes, the arriving air masses spent recent days over desert areas (e.g., the Saharan Desert in North Africa). On days with regionally low PM2.5 concentrations (≈20 µg/m3), back trajectory analysis showed that air masses were directed in from the Mediterranean Sea area. Further, the lower elevation (downtown) site often recorded markedly higher particulate levels than the valley wall sites. This would suggest locally derived particulate sources are significant and may be beneficial in the identification of potential remediation options.

scholarly journals Evolution of the Distribution of Upper-Tropospheric Humidity over the Indian Ocean: Connection with Large-Scale Advection and Local Cloudiness

2017 ◽  
Vol 56 (7) ◽  
pp. 2035-2052 ◽  
Author(s):  
Thomas Garot ◽  
Hélène Brogniez ◽  
Renaud Fallourd ◽  
Nicolas Viltard
Keyword(s):  
Indian Ocean ◽  
Large Scale ◽  
Transport Model ◽  
Intraseasonal Variability ◽  
Back Trajectory ◽  
Time Step ◽  
Air Masses ◽  
Upper Troposphere ◽  
Upper Tropospheric Humidity ◽  
The Indian Ocean

AbstractThe spatial and temporal distribution of upper-tropospheric humidity (UTH) observed by the Sounder for Atmospheric Profiling of Humidity in the Intertropics by Radiometry (SAPHIR)/Megha-Tropiques radiometer is analyzed over two subregions of the Indian Ocean during October–December over 2011–14. The properties of the distribution of UTH were studied with regard to the phase of the Madden–Julian oscillation (active or suppressed) and large-scale advection versus local production of moisture. To address these topics, first, a Lagrangian back-trajectory transport model was used to assess the role of the large-scale transport of air masses in the intraseasonal variability of UTH. Second, the temporal evolution of the distribution of UTH is analyzed using the computation of the higher moments of its probability distribution function (PDF) defined for each time step over the domain. The results highlight significant differences in the PDF of UTH depending on the phase of the MJO. The modeled trajectories ending in the considered domain originate from an area that strongly varies depending on the phases of the MJO: during the active phases, the air masses are spatially constrained within the tropical Indian Ocean domain, whereas a distinct upper-tropospheric (200–150 hPa) westerly flow guides the intraseasonal variability of UTH during the suppressed phases. Statistical relationships between the cloud fractions and the UTH PDF moments of are found to be very similar regardless of the convective activity. However, the occurrence of thin cirrus clouds is associated with a drying of the upper troposphere (enhanced during suppressed phases), whereas the occurrence of thick cirrus anvil clouds appears to be significantly related to a moistening of the upper troposphere.

scholarly journals An investigation of processes controlling the evolution of the boundary layer aerosol size distribution properties at the Swedish background station Aspvreten

2004 ◽  
Vol 4 (4) ◽  
pp. 4507-4543 ◽  
Author(s):  
P. Tunved ◽  
J. Ström ◽  
H.-C. Hansson
Keyword(s):  
Size Distribution ◽  
Wet Deposition ◽  
Source Area ◽  
Aerosol Size Distribution ◽  
Back Trajectory ◽  
Main Process ◽  
Size Distributions ◽  
Back Trajectory Analysis ◽  
The One ◽  
Precipitating Clouds

Abstract. Aerosol size distributions have been measured at the Swedish background station Aspvreten (58.8° N, 17.4° E). Different states of the aerosol were determined using a novel application of cluster analysis. The analysis resulted in eight different clusters capturing the different stages of the aerosol lifecycle. The aerosol was interpreted as belonging to fresh, intermediate and aged type of size distribution and different magnitudes thereof. With aid of back trajectory analysis we present statistics concerning the relation of source area and different meteorological parameters using a non-lagrangian approach. Source area is argued to be important although not sufficient to describe the observed aerosol properties. Especially processing by clouds and precipitation is shown to be crucial for the evolution of the aerosol size distribution. As much as 60% of the observed size distributions present features likely related to cloud processes or wet deposition. The lifetime properties of different sized aerosols are discussed by means of measured variability. Processing by non-precipitating clouds most obviously affect aerosols in the size range 100 nm and larger. This indicates an approximate limit for activation in clouds to 100 nm in this type of environment. The aerosol lifecycle is discussed. Size distributions bearing signs of recent new particle formation (~30% of the observed size distributions) represent the first stage in the lifecycle. Aging may proceed in two directions: either growth by condensation and coagulation or processing by non-precipitating clouds. In both cases mass is accumulated. Wet removal is the main process capable of removing aerosol mass. Wet deposition is argued to be an important mechanism in reaching a state where nucleation may occur (i.e. sufficiently low aerosol surface area) in environments similar to the one studied.

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