scholarly journals Source apportionment of atmospheric water over East Asia – a source tracer study in CAM5.1

2017 ◽  
Vol 10 (2) ◽  
pp. 673-688 ◽  
Author(s):  
Chen Pan ◽  
Bin Zhu ◽  
Jinhui Gao ◽  
Hanqing Kang
Keyword(s):  
East Asia ◽  
Source Apportionment ◽  
Water Vapour ◽  
Southern China ◽  
Source Region ◽  
Summer Precipitation ◽  
Small Contribution ◽  
Atmospheric Water ◽  
Transport Pathway ◽  
Moisture Source

Abstract. The atmospheric water tracer (AWT) method is implemented in the Community Atmosphere Model version 5.1 (CAM5.1) to quantitatively identify the contributions of various source regions to precipitation and water vapour over East Asia. Compared to other source apportionment methods, the AWT method was developed based on detailed physical parameterisations, and can therefore trace the behaviour of atmospheric water substances directly and exactly. According to the simulation, the northern Indian Ocean (NIO) is the dominant oceanic moisture source region for precipitation over the Yangtze River valley (YRV) and southern China (SCN) in summer, while the north-western Pacific (NWP) dominates during other seasons. Evaporation over the South China Sea (SCS) is responsible for only 2.7–3.7 % of summer precipitation over the YRV and SCN. In addition, the Indo-China Peninsula is an important terrestrial moisture source region (annual contribution of  ∼  10 %). The overall relative contribution of each source region to the water vapour amount is similar to the corresponding contribution to precipitation over the YRV and SCN. A case study for the SCS shows that only a small part ( ≤  5.5 %) of water vapour originates from local evaporation, whereas much more water vapour is supplied by the NWP and NIO. In addition, because evaporation from the SCS represents only a small contribution to the water vapour over the YRV and SCN in summer, the SCS mainly acts as a water vapour transport pathway where moisture from the NIO and NWP meet.

scholarly journals Source apportionment of atmospheric water over East Asia – a source tracer study in CAM5.1

2016 ◽  
Author(s):  
Chen Pan ◽  
Bin Zhu ◽  
Jinhui Gao ◽  
Hanqing Kang
Keyword(s):  
East Asia ◽  
Source Apportionment ◽  
Water Vapour ◽  
South China ◽  
Source Region ◽  
Northwest Pacific ◽  
Small Contribution ◽  
Atmospheric Water ◽  
Transport Pathway ◽  
Moisture Source

Abstract. The atmospheric water tracer (AWT) method is implemented in the Community Atmosphere Model version 5.1 (CAM5.1) to quantitatively identify the contributions of various source regions to precipitation and water vapour over East Asia. Compared to other source apportionment methods, the AWT method was developed based on detailed physical parameterizations, and can therefore trace the behaviour of atmospheric water substances directly and exactly. According to the simulation, the north Indian Ocean (NIO) is the dominant oceanic moisture source region for precipitation over the Yangtze River Valley (YRV) and South China (SCN) in summer, while the Northwest Pacific (NWP) dominates during other seasons. Evaporation over the South China Sea (SCS) is responsible for only 2.8–4.2 % of summer precipitation over the YRV and SCN. In addition, the Indo-China Peninsula is an important terrestrial moisture source region (annual contribution of ~ 10 %). The overall relative contribution of each source region to the water vapour amount is similar to the corresponding contribution to precipitation over the YRV and SCN. A case study for the SCS shows that only a small part (≤ 5.8 %) of water vapour originates from local evaporation, while much more water vapour is supplied by the NWP and NIO. In addition, because evaporation from the SCS represents only a small contribution to the water vapour over the YRV and SCN in summer, the SCS mainly acts as a water vapour transport pathway where moisture from the NIO and NWP meet.

scholarly journals A Global Oxygen Isotope Model – Semi-Empirical, Zonally Averaged

1985 ◽  
Vol 7 ◽  
pp. 117-124 ◽  
Author(s):  
D.A. Fisher ◽  
B.T. Alt
Keyword(s):  
Water Vapour ◽  
Source Region ◽  
Ice Core ◽  
Salt Content ◽  
Type Model ◽  
Polar Regions ◽  
Atmospheric Water ◽  
Atmospheric Water Vapour ◽  
Equal Importance ◽  
Semi Empirical

A simple model, which is zonally averaged, for the transport of atmospheric water vapour is presented which uses as input the zonally averaged evaporation field and the mean meridional travel distance of tropospheric water vapour as functions of latitude. The model demonstrates that for polar regions each of the 10° latitude strips poleward of 25° is of equal importance as a moisture source. The model is used to predict zonal averages of δ(18O) for the present day and 18 ka BP. Both annual average values and seasonal amplitudes are presented and compared to observations. Sea-ice cover is an important factor in determining both annual averages and seasonal amplitudes today and at 18 ka BP. An earlier model (Jouzel and others 1983) linking δ(18O), the deuterium excess, and sea-salt content in an Antarctic ice core to the relative humidity of the source region is based on a single-source atmospheric water-vapour cycle type model and is re-evaluated using the present model.

scholarly journals Evaluating the influences of biomass burning during 2006 BASE-ASIA: a regional chemical transport modeling

2012 ◽  
Vol 12 (9) ◽  
pp. 3837-3855 ◽  
Author(s):  
J. S. Fu ◽  
N. C. Hsu ◽  
Y. Gao ◽  
K. Huang ◽  
C. Li ◽  
...  
Keyword(s):  
Southeast Asia ◽  
East Asia ◽  
Long Range ◽  
Biomass Burning ◽  
Cross Sections ◽  
Southern China ◽  
Source Region ◽  
Long Range Transport ◽  
Range Transport ◽  
The Impact

Abstract. To evaluate the impact of biomass burning from Southeast Asia to East Asia, this study conducted numerical simulations during NASA's 2006 Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment (BASE-ASIA). Two typical episode periods (27–28 March and 13–14 April) were examined. Two emission inventories, FLAMBE and GFED, were used in the simulations. The influences during two episodes in the source region (Southeast Asia) contributed to the surface CO, O3 and PM2.5 concentrations as high as 400 ppbv, 20 ppbv and 80 μg m−3, respectively. The perturbations with and without biomass burning of the above three species during the intense episodes were in the range of 10 to 60%, 10 to 20% and 30 to 70%, respectively. The impact due to long-range transport could spread over the southeastern parts of East Asia and could reach about 160 to 360 ppbv, 8 to 18 ppbv and 8 to 64 μg m−3 on CO, O3 and PM2.5, respectively; the percentage impact could reach 20 to 50% on CO, 10 to 30% on O3, and as high as 70% on PM2.5. In March, the impact of biomass burning mainly concentrated in Southeast Asia and southern China, while in April the impact becomes slightly broader and even could go up to the Yangtze River Delta region. Two cross-sections at 15° N and 20° N were used to compare the vertical flux of biomass burning. In the source region (Southeast Asia), CO, O3 and PM2.5 concentrations had a strong upward transport from surface to high altitudes. The eastward transport becomes strong from 2 to 8 km in the free troposphere. The subsidence process during the long-range transport contributed 60 to 70%, 20 to 50%, and 80% on CO, O3 and PM2.5, respectively to surface in the downwind area. The study reveals the significant impact of Southeastern Asia biomass burning on the air quality in both local and downwind areas, particularly during biomass burning episodes. This modeling study might provide constraints of lower limit. An additional study is underway for an active biomass burning year to obtain an upper limit and climate effects.

scholarly journals Comparing CAM5 and Superparameterized CAM5 Simulations of Summer Precipitation Characteristics over Continental East Asia: Mean State, Frequency–Intensity Relationship, Diurnal Cycle, and Influencing Factors

2016 ◽  
Vol 29 (3) ◽  
pp. 1067-1089 ◽  
Author(s):  
Yi Zhang ◽  
Haoming Chen
Keyword(s):  
East Asia ◽  
Southern China ◽  
Deep Convection ◽  
Summer Precipitation ◽  
Western China ◽  
Peak Time ◽  
Modeling Framework ◽  
Precipitation Frequency ◽  
Diurnal Variability ◽  
Hourly Precipitation

Abstract Numerical experiments are conducted to investigate the differences between summer precipitation over continental East Asia simulated by the Community Atmosphere Model, version 5 (CAM5), and superparameterized CAM5 (SPCAM5, a multiscale modeling framework). The results show that SPCAM5 effectively alleviates several original biases. Overestimates of precipitation on the eastern periphery of the Tibetan Plateau are reduced from CAM5 to SPCAM5 as a result of decreases in both the average hourly precipitation frequency and mean hourly intensity. Underestimates along the coastal regions in southern China are improved following a corresponding increase in mean hourly intensity and a decrease in average hourly precipitation frequency. The frequency–intesnsity relationship is also more realistic in SPCAM5. For western China, overestimated frequency values (in CAM5) of both weak-to-moderate (0–20 mm day−1) and heavy (20–50 mm day−1) intensity ranges are reduced in SPCAM5. For southern China, overestimates of frequency values (in CAM5) in the weak-to-moderate range are also reduced, whereas underestimates in the intense ranges are enhanced. In terms of diurnal variability, SPCAM5 generally exhibits a delay in the afternoon peak time and greater diurnal amplitude. The possible physical reasons for the variations in the precipitation between the models are further investigated. It is found that the change in deep convection intensity is a primary factor governing the shift in the precipitation simulations. SPCAM5 better simulates an intermediate transition stage from shallow to deep convection, which helps the deep convection to grow more fully to a greater magnitude, thus delaying the peak time and increasing the precipitation maxima.

scholarly journals Evaluating the influences of biomass burning during 2006 BASE-ASIA: a regional chemical transport modeling

2011 ◽  
Vol 11 (12) ◽  
pp. 32205-32243 ◽  
Author(s):  
J. S. Fu ◽  
N. C. Hsu ◽  
Y. Gao ◽  
K. Huang ◽  
C. Li ◽  
...  
Keyword(s):  
Southeast Asia ◽  
East Asia ◽  
Long Range ◽  
Biomass Burning ◽  
Cross Sections ◽  
Southern China ◽  
Source Region ◽  
Long Range Transport ◽  
Range Transport ◽  
The Impact

Abstract. To evaluate the impact of biomass burning from Southeast Asia to East Asia, this study conducted numerical simulations during NASA's 2006 Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment (BASE-ASIA). Two typical episode periods (27–28 March and 13–14 April) were examined. Two emission inventories, FLAMBE and GFED, were used in the simulations. The influences during two episodes in the source region (Southeast Asia) contributed to the surface CO, O3 and PM2.5 concentrations as high as 400 ppbv, 20 ppbv and 80 μg m−3, respectively. The perturbations with and without biomass burning of the above three species during the intense episodes were in the range of 10 to 60%, 10 to 20% and 30 to 70%, respectively. The impact due to long-range transport could spread over the southeastern parts of East Asia and could reach about 160 to 360 ppbv, 8 to 18 ppbv and 8 to 64 μg m−3 on CO, O3 and PM2.5, respectively; the percentage impact could reach 20 to 50% on CO, 10 to 30% on O3, and as high as 70% on PM2.5. In March, the impact of biomass burning was mainly concentrated in Southeast Asia and Southern China, while in April the impact becomes slightly broader, potentially including the Yangtze River Delta region. Two cross-sections at 15° N and 20° N were used to compare the vertical flux of biomass burning. In the source region (Southeast Asia), CO, O3 and PM2.5 concentrations had a strong upward transport from surface to high altitudes. The eastward transport becomes strong from 2 to 8 km in the free troposphere. The subsidence process during the long-range transport contributed 60 to 70%, 20 to 50%, and 80% to CO, O3 and PM2.5, respectively to surface in the downwind area. The study reveals the significant impact of Southeastern Asia biomass burning on the air quality in both local and downwind areas, particularly during biomass burning episodes. This modeling study might provide lower limit constraints. An additional study is underway for an active biomass burning year to obtain an upper limit and climate effects.

scholarly journals A Global Oxygen Isotope Model – Semi-Empirical, Zonally Averaged

1985 ◽  
Vol 7 ◽  
pp. 117-124 ◽  
Author(s):  
D.A. Fisher ◽  
B.T. Alt
Keyword(s):  
Water Vapour ◽  
Source Region ◽  
Ice Core ◽  
Salt Content ◽  
Type Model ◽  
Polar Regions ◽  
Atmospheric Water ◽  
Atmospheric Water Vapour ◽  
Equal Importance ◽  
Semi Empirical

A simple model, which is zonally averaged, for the transport of atmospheric water vapour is presented which uses as input the zonally averaged evaporation field and the mean meridional travel distance of tropospheric water vapour as functions of latitude. The model demonstrates that for polar regions each of the 10° latitude strips poleward of 25° is of equal importance as a moisture source. The model is used to predict zonal averages of δ(18O) for the present day and 18 ka BP. Both annual average values and seasonal amplitudes are presented and compared to observations. Sea-ice cover is an important factor in determining both annual averages and seasonal amplitudes today and at 18 ka BP. An earlier model (Jouzel and others 1983) linking δ(18O), the deuterium excess, and sea-salt content in an Antarctic ice core to the relative humidity of the source region is based on a single-source atmospheric water-vapour cycle type model and is re-evaluated using the present model.

Combined Effects of Synoptic-Scale Teleconnection Patterns on Summer Precipitation in Southern China

2020 ◽  
Author(s):  
Chao Wang
Keyword(s):  
East Asia ◽  
Extreme Precipitation ◽  
Southern China ◽  
Summer Precipitation ◽  
Western Pacific Subtropical High ◽  
Asia Pacific ◽  
Combined Effects ◽  
Teleconnection Patterns ◽  
South Asia High ◽  
Westerly Jet

<p>Using ERA-Interim daily reanalysis and precipitation data, the combined effects of East Asia-Pacific (EAP) and Silk Road (SR) teleconnection patterns on summer precipitation in southern China were investigated on synoptic to sub-monthly timescales. Combined EAP and SR patterns lead to more persistent and extreme precipitation in the Yangtze River Valley (YRV) and exhibit an obvious zonal advance between the South Asia High (SAH) and Western Pacific Subtropical High (WPSH) prior to its onset. During typical combined events, an overlap between the SAH and WPSH remains in a favorable position for Persistent Extreme Precipitation (PEP). Furthermore, SR-induced acceleration of the westerly jet stream and extra positive vorticity advection provide persistent upper-level divergence for YRV precipitation. An anomalous EAP-related cyclone/anticyclone pair over East Asia induces enhanced low-level southwesterlies to the northern anticyclone flank and northerlies from the mid-latitudes, advecting anomalously abundant moisture toward the YRV, resulting in clear moisture convergence. Moreover, the strong ascent of warmer/moister air along a quasi-stationary front may be crucial for PEP. During decay, the SAH and WPSH diverge from each other and retreat to their normal positions, and the strong ascent of warmer/moister air rapidly weakens to dissipation, terminating PEP in the YRV.</p>

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