scholarly journals Examination of aerosol impacts on convective clouds and precipitation in two metropolitan areas in East Asia; how varying depths of convective clouds between the areas diversify those aerosol effects?

2021 ◽  
Author(s):  
Seoung Soo Lee ◽  
Jinho Choi ◽  
Goun Kim ◽  
Kyung-Ja Ha ◽  
Kyong-Hwan Seo ◽  
...  
Keyword(s):  
East Asia ◽  
Metropolitan Areas ◽  
Precipitation Amount ◽  
Heavy Precipitation ◽  
Beijing Area ◽  
Convective Clouds ◽  
Different Types ◽  
Aerosol Effects ◽  
Induced Changes ◽  
Light Medium

Abstract. This study examines the role played by aerosols in the development of clouds and precipitation in two metropolitan areas in East Asia that has experienced substantial increases in aerosol concentrations over the last decades. These two areas are the Seoul and Beijing areas and the examination has been done by performing simulations using a cloud-system resolving model (CSRM). Aerosols are advected from the continent to the Seoul area and this increases aerosol concentrations in the Seoul area. These increased aerosol concentrations induce the enhancement of condensation that in turn induces the enhancement of deposition and precipitation amount in a system of less deep convective clouds as compared to those in the Beijing area. In a system of deeper clouds in the Beijing area, increasing aerosol concentrations also enhance condensation but reduce deposition. This leads to aerosol-induced negligible changes in precipitation amount. Also, in the system, there is a competition for convective energy among clouds with different condensation and updrafts. This competition results in different responses to increasing aerosol concentrations among different types of precipitation, which are light, medium and heavy precipitation in the Beijing area. In both of the areas, aerosol-induced changes in freezing play a negligible role in aerosol-precipitation interactions as compared to the role played by aerosol-induced changes in condensation and deposition.

scholarly journals Aerosol effects on the cloud-field properties of tropical convective clouds

2013 ◽  
Vol 13 (1) ◽  
pp. 2997-3029 ◽  
Author(s):  
S.-S. Lee ◽  
G. Feingold
Keyword(s):  
Frequency Distribution ◽  
Mass Flux ◽  
Temporal Evolution ◽  
Precipitation Amount ◽  
Fold Increase ◽  
Convective Clouds ◽  
Condensed Water ◽  
Microphysical Processes ◽  
Aerosol Effects ◽  
Convective Mass Flux

Abstract. Aerosol effects on condensed water and precipitation in a tropical cloud system driven by deep convective clouds are investigated for two-dimensional simulations of two-day duration. Although an assumed ten-fold increase in aerosol concentration results in a similar temporal evolution of mean precipitation and a small (9%) difference in cumulative precipitation between the high- and low-aerosol cases, the characteristics of the convection are much more sensitive to aerosol. The convective mass flux, and temporal evolution and frequency distribution of the condensed water path WP (sum of liquid and ice water paths) differ significantly between unperturbed and aerosol-perturbed simulations. There are concomitant differences in the relative importance of individual microphysical processes and the frequency distribution of the precipitation rate (P). With increasing aerosol, (i) the convective mass flux increases, leading to increases in condensation, cloud liquid, and accretion of cloud liquid by precipitation; (ii) autoconversion of cloud water to rain water decreases; (iii) the WP spatial distribution becomes more homogeneous; (iv) there is an increase in the frequencies of high and low WP and P and a decrease in these frequencies at the mid-range of WP and P. Thus while aerosol perturbations have a negligible influence on total precipitation amount, for the case considered, they do have substantial influence on the spatiotemporal distribution of convection and precipitation.

scholarly journals Aerosol effects on the cloud-field properties of tropical convective clouds

2013 ◽  
Vol 13 (14) ◽  
pp. 6713-6726 ◽  
Author(s):  
S.-S. Lee ◽  
G. Feingold
Keyword(s):  
Frequency Distribution ◽  
Mass Flux ◽  
Temporal Evolution ◽  
Precipitation Amount ◽  
Fold Increase ◽  
Convective Clouds ◽  
Condensed Water ◽  
Microphysical Processes ◽  
Aerosol Effects ◽  
Convective Mass Flux

Abstract. Aerosol effects on condensed water and precipitation in a tropical cloud system driven by deep convective clouds are investigated for two-dimensional simulations of 2-day duration. Although an assumed 10-fold increase in aerosol concentration results in a similar temporal evolution of mean precipitation and a small (9%) difference in cumulative precipitation between the high- and low-aerosol cases, the characteristics of the convection are much more sensitive to aerosol. The convective mass flux, and temporal evolution and frequency distribution of the condensed water path WP (sum of liquid- and ice-water paths) differ significantly between unperturbed and aerosol-perturbed simulations. There are concomitant differences in the relative importance of individual microphysical processes and the frequency distribution of the precipitation rate (P). With increasing aerosol (i) the convective mass flux increases, leading to increases in condensation, cloud liquid, and accretion of cloud liquid by precipitation; (ii) autoconversion of cloud water to rain water decreases; (iii) the WP spatial distribution becomes more homogeneous; and (iv) there is an increase in the frequencies of high and low WP and P, and a decrease in these frequencies at the mid-range of WP and P. Thus, while aerosol perturbations have a small influence on total precipitation amount, for the case considered, they do have substantial influence on the spatiotemporal distribution of convection and precipitation.

scholarly journals IAP-AACM v1.0： Global to regional evaluation of the atmospheric chemistry model in CAS-ESM

2018 ◽  
Author(s):  
Ying Wei ◽  
Xueshun Chen ◽  
Huansheng Chen ◽  
Jie Li ◽  
Zifa Wang ◽  
...  
Keyword(s):  
East Asia ◽  
Spatial Variation ◽  
Atmospheric Chemistry ◽  
Comprehensive Evaluation ◽  
Correlation Coefficients ◽  
Full Description ◽  
Atmospheric Physics ◽  
Temporal And Spatial Variability ◽  
Fine Mode ◽  
Aerosol Effects

Abstract. In this study, a full description and comprehensive evaluation of a global-regional nested model, the Aerosol and Atmospheric Chemistry Model of the Institute of Atmospheric Physics (IAP-AACM), is presented for the first time. Not only the global budgets and distribution, but also a comparison of nested simulation over China against multi-datasets are investigated, benefiting from the access of air quality monitoring data in China since 2013 and the Model Inter-Comparison Study for Asia project. The model results and analysis can greatly help reduce uncertainties and understand model diversity in assessing global and regional aerosol effects, especially over East Asia and areas affected by East Asia. The 1-year simulation for 2014 shows that the IAP-AACM is within the range of other models, and well reproduces both spatial distribution and seasonal variation of trace gases and aerosols over major continents and oceans (mostly within the factor of two). The model nicely captures spatial variation for carbon monoxide except an underestimation over the ocean that also shown in other models, which suggests the need for more accurate emission rate of ocean source. For aerosols, the simulation of fine-mode particulate matter (PM2.5) matches observation well and it has a better simulating ability on primary aerosols than secondary aerosols. This calls for more investigation on aerosol chemistry. Furthermore, IAP-AACM shows the superiority of global model, compared with regional model, on performing regional transportation for the nested simulation over East Asia. For the city evaluation over China, the model reproduces variation of sulfur dioxide (SO2), nitrogen dioxide (NO2) and PM2.5 accurately in most cities, with correlation coefficients above 0.5. Compared to the global simulation, the nested simulation exhibits an improved ability to capture the high temporal and spatial variability over China. In particular, the correlation coefficients for PM2.5, SO2 and NO2 are raised by ~ 0.25, ~ 0.15 and ~ 0.2 respectively in the nested grid. The summary provides constructive information for the application of chemical transport models. In future, we recommend the model's ability to capture high spatial variation of PM2.5 is yet to be improved.

scholarly journals Sulfate geoengineering: a review of the factors controlling the needed injection of sulfur dioxide

2016 ◽  
Author(s):  
Daniele Visioni ◽  
Giovanni Pitari ◽  
Valentina Aquila
Keyword(s):  
Lower Stratosphere ◽  
Effective Means ◽  
Climate Engineering ◽  
Radiative Effects ◽  
Stratospheric Water Vapor ◽  
Long Wave ◽  
Engineering Technique ◽  
Aerosol Effects ◽  
Induced Changes ◽  
Fine Tune

Abstract. Sulfate geoengineering has been proposed as an affordable and climate-effective means for temporarily offset the warming produced by the increase of well mixed greenhouse gases (WMGHG). This climate engineering technique has been planned for a timeframe of a few decades needed to implement global inter-governmental measures needed to achieve stabilization of the atmospheric content of WMGHGs (CO2 in particular). The direct radiative effects of sulfur injection in the tropical lower stratosphere can be summarized as increasing shortwave scattering with consequent tropospheric cooling and increasing long- wave absorption with stratospheric warming. Indirect radiative effects are related to induced changes in the ozone distribution, stratospheric water vapor abundance, formation and size of upper tropospheric cirrus ice particles and lifetime of longlived species, namely CH4 in connection with OH changes through several photochemical mechanisms. A direct comparison of the net effects of WMGHG increase with direct and indirect effects of sulfate geoengineering may help fine-tune the best amount of sulfate to be injected in an eventual realization of the experiment. However, we need to take into account large uncertainties in the estimate of some of these aerosol effects, such as cirrus ice particle size modifications.

scholarly journals How do changes in warm-phase microphysics affect deep convective clouds?

2017 ◽  
Vol 17 (15) ◽  
pp. 9585-9598 ◽  
Author(s):  
Qian Chen ◽  
Ilan Koren ◽  
Orit Altaratz ◽  
Reuven H. Heiblum ◽  
Guy Dagan ◽  
...  
Keyword(s):  
Rain Rate ◽  
Convective Cloud ◽  
Cloud Fraction ◽  
Marshall Islands ◽  
Cloud System ◽  
Main Question ◽  
Convective Clouds ◽  
Deep Convective Clouds ◽  
Aerosol Effects ◽  
Deep Convective Cloud

Abstract. Understanding aerosol effects on deep convective clouds and the derived effects on the radiation budget and rain patterns can largely contribute to estimations of climate uncertainties. The challenge is difficult in part because key microphysical processes in the mixed and cold phases are still not well understood. For deep convective clouds with a warm base, understanding aerosol effects on the warm processes is extremely important as they set the initial and boundary conditions for the cold processes. Therefore, the focus of this study is the warm phase, which can be better resolved. The main question is: How do aerosol-derived changes in the warm phase affect the properties of deep convective cloud systems? To explore this question, we used a weather research and forecasting (WRF) model with spectral bin microphysics to simulate a deep convective cloud system over the Marshall Islands during the Kwajalein Experiment (KWAJEX). The model results were validated against observations, showing similarities in the vertical profile of radar reflectivity and the surface rain rate. Simulations with larger aerosol loading resulted in a larger total cloud mass, a larger cloud fraction in the upper levels, and a larger frequency of strong updrafts and rain rates. Enlarged mass both below and above the zero temperature level (ZTL) contributed to the increase in cloud total mass (water and ice) in the polluted runs. Increased condensation efficiency of cloud droplets governed the gain in mass below the ZTL, while both enhanced condensational and depositional growth led to increased mass above it. The enhanced mass loading above the ZTL acted to reduce the cloud buoyancy, while the thermal buoyancy (driven by the enhanced latent heat release) increased in the polluted runs. The overall effect showed an increased upward transport (across the ZTL) of liquid water driven by both larger updrafts and larger droplet mobility. These aerosol effects were reflected in the larger ratio between the masses located above and below the ZTL in the polluted runs. When comparing the net mass flux crossing the ZTL in the clean and polluted runs, the difference was small. However, when comparing the upward and downward fluxes separately, the increase in aerosol concentration was seen to dramatically increase the fluxes in both directions, indicating the aerosol amplification effect of the convection and the affected cloud system properties, such as cloud fraction and rain rate.

The “Greater East Asia Co-prosperity Sphere”: A New Boundary for Taiwanese People and the Taiwanese Capital, 1940–1945 (臺灣人的對外移民與投資, 1940–1945)

2016 ◽  
Vol 10 (2) ◽  
pp. 175-206 ◽  
Author(s):  
Man-houng Lin (林滿紅)
Keyword(s):  
East Asia ◽  
East Asian ◽  
Asia Pacific ◽  
Overseas Chinese ◽  
Pacific War ◽  
Ethnic Chinese ◽  
Different Types ◽  
Taiwanese People ◽  
Overseas Investment ◽  
Direction Opposite

This article deals with Taiwanese civilian emigration and overseas investment in the period of 1940–1945 when Japan engaged the Greater East Asian War. Taiwan in general, and some Taiwanese in particular, helped the reconstruction of Japanese occupied areas in this war. Overseas Taiwanese mainly worked as employees for Japanese stores, companies, mines, plantations, and Japanese government offices, but also opened stores, factories, plantations and banks by themselves. As overseas ethnic Chinese, the Taiwanese civilian emigrants examined in this paper moved in the direction opposite that of other overseas Chinese holding Chinese nationality. The Taiwanese populace expanded overseas to Greater East Asia, while Chinese nationals withdrew from this area and returned to China. Thus, this paper will illustrate how the phrase, “people should fight for their country,” bore different meanings for these two different types of overseas Chinese in the Asia-Pacific War theater of wwii. 1930至40年代，中日學者曾就華僑的定義進行討論。吳主惠將華僑定義為定居於海外的中國人及其後裔，不包括駐外政府官員和留學生。吳氏認為華僑的最嚴格定義，是指定居海外但仍保有中國國籍者。1933年日本大藏省為替局統計臺灣地區約有46,000至47,000名華僑，便是依據這樣的定義。吳氏指出，在此嚴格定義下，華人後裔如不具中國國籍者，便非華僑。另有一種較為寬鬆的定義是: 無論是否具中國國籍，凡定居或曾赴海外的中國人及其後裔皆為華僑，井出季和太即持此見。關於日本統治臺灣時期的臺灣人國籍，根據日本大藏省為替局的解釋，由於馬關條約簽訂後的二年內，臺灣人得自由決定離去與否，留下臺灣者為日本國民。這些成為日本國民的臺灣人或其祖先曾具有中國國民的身分，因而1933年的340萬臺灣人也被視為較寬定義下的華僑。在日本建構所謂的「大東亞共榮圈」時期 (1940–1945)，許多不具軍人身分的臺灣人向海外移民或投資，與之相反的是，擁有中國國籍的華僑在此時期則多回歸故里。在大東亞戰爭時期的華人，由於出身不同，「為國而戰」一詞對於他們的意義也因而分歧。 (This article is in English.)

scholarly journals A Novel Multi-Input Multi-Output Recurrent Neural Network Based on Multimodal Fusion and Spatiotemporal Prediction for 0–4 h Precipitation Nowcasting

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1596
Author(s):  
Fuhan Zhang ◽  
Xiaodong Wang ◽  
Jiping Guan
Keyword(s):  
Neural Network ◽  
Recurrent Neural Network ◽  
Input Data ◽  
Learning Strategy ◽  
Meteorological Data ◽  
Precipitation Amount ◽  
Heavy Precipitation ◽  
Precipitation Intensity ◽  
Multimodal Fusion ◽  
Grid Data

Multi-source meteorological data can reflect the development process of single meteorological elements from different angles. Making full use of multi-source meteorological data is an effective method to improve the performance of weather nowcasting. For precipitation nowcasting, this paper proposes a novel multi-input multi-output recurrent neural network model based on multimodal fusion and spatiotemporal prediction, named MFSP-Net. It uses precipitation grid data, radar echo data, and reanalysis data as input data and simultaneously realizes 0–4 h precipitation amount nowcasting and precipitation intensity nowcasting. MFSP-Net can perform the spatiotemporal-scale fusion of the three sources of input data while retaining the spatiotemporal information flow of them. The multi-task learning strategy is used to train the network. We conduct experiments on the dataset of Southeast China, and the results show that MFSP-Net comprehensively improves the performance of the nowcasting of precipitation amounts. For precipitation intensity nowcasting, MFSP-Net has obvious advantages in heavy precipitation nowcasting and the middle and late stages of nowcasting.

scholarly journals Detectable Anthropogenic Influence on Changes in Summer Precipitation in China

2020 ◽  
Vol 33 (13) ◽  
pp. 5357-5369
Author(s):  
Chunhui Lu ◽  
Fraser C. Lott ◽  
Ying Sun ◽  
Peter A. Stott ◽  
Nikolaos Christidis
Keyword(s):  
Human Life ◽  
Eastern China ◽  
Precipitation Amount ◽  
Summer Precipitation ◽  
Heavy Precipitation ◽  
Observation Data ◽  
Anthropogenic Influence ◽  
Anthropogenic Forcing ◽  
The Future ◽  
Light Precipitation

AbstractIn China, summer precipitation contributes a major part of the total precipitation amount in a year and has major impacts on society and human life. Whether any changes in summer precipitation are affected by external forcing on the climate system is an important issue. In this study, an optimal fingerprinting method was used to compare the observed changes of total, heavy, moderate, and light precipitation in summer derived from newly homogenized observation data with the simulations from multiple climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). The results demonstrate that the anthropogenic forcing signal can be detected and separated from the natural forcing signal in the observed increase of seasonal accumulated precipitation amount for heavy precipitation in summer in China and eastern China (EC). The simulated changes in heavy precipitation are generally consistent with observed change in China but are underestimated in EC. When the changes in precipitation of different intensities are considered simultaneously, the human influence on simultaneous changes in moderate and light precipitation can be detected in China and EC in summer. Changes attributable to anthropogenic forcing explain most of the observed regional changes for all categories of summer precipitation, and natural forcing contributes little. In the future, with increasing anthropogenic influence, the attribution-constrained projection suggests that heavy precipitation in summer will increase more than that from the model raw outputs. Society may therefore face a higher risk of heavy precipitation in the future.

scholarly journals Observed Changes of Rain-Season Precipitation in China from 1960 to 2018

2021 ◽  
Vol 18 (19) ◽  
pp. 10031
Author(s):  
Yanyu Zhang ◽  
Shuying Zang ◽  
Xiangjin Shen ◽  
Gaohua Fan
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
Precipitation Amount ◽  
Heavy Precipitation ◽  
Central China ◽  
The Tibetan Plateau ◽  
Natural Ecosystems ◽  
Daily Precipitation Data ◽  
Rain Season

Precipitation during the main rain season is important for natural ecosystems and human activities. In this study, according to daily precipitation data from 515 weather stations in China, we analyzed the spatiotemporal variation of rain-season (May–September) precipitation in China from 1960 to 2018. The results showed that rain-season precipitation decreased over China from 1960 to 2018. Rain-season heavy (25 ≤ p < 50 mm/day) and very heavy (p ≥ 50 mm/day) precipitation showed increasing trends, while rain-season moderate (10 ≤ p < 25 mm/day) and light (0.1 ≤ p < 10 mm/day) precipitation showed decreasing trends from 1960 to 2018. The temporal changes of precipitation indicated that rain-season light and moderate precipitation displayed downward trends in China from 1980 to 2010 and rain-season heavy and very heavy precipitation showed fluctuant variation from 1960 to 2018. Changes of rain-season precipitation showed clear regional differences. Northwest China and the Tibetan Plateau showed the largest positive trends of precipitation amount and days. In contrast, negative trends were found for almost all precipitation grades in North China Plain, Northeast China, and North Central China. Changes toward drier conditions in these regions probably had a severe impact on agricultural production. In East China, Southeast China and Southwest China, heavy and very heavy precipitation had increased while light and moderate precipitation had decreased. This result implied an increasing risk of flood and mudslides in these regions. The advance in understanding of precipitation change in China will contribute to exactly predict the regional climate change under the background of global climate change.

scholarly journals Dissimilar mechanisms of Ca2+response to bradykinin in different types of juxtamedullary glomerular arterioles

1999 ◽  
Vol 277 (5) ◽  
pp. F697-F705 ◽  
Author(s):  
F. Praddaude ◽  
J. Marchetti ◽  
F. Alhenc-Gelas ◽  
J.-L. Ader
Keyword(s):  
Tyrosine Kinases ◽  
Maximal Response ◽  
Lower Sensitivity ◽  
Free Medium ◽  
Herbimycin A ◽  
Intracellular Calcium Level ◽  
Different Types ◽  
Intracellular Ca ◽  
Induced Changes ◽  
Glomerular Arterioles

Bradykinin (BK)-induced changes in intracellular calcium level ([Ca2+]i) were studied on fura 2-loaded afferent (AA) and efferent glomerular arterioles (EA) microdissected from juxtamedullary renal cortex. A distinction was made between thin and muscular EA. In AA and both types of EA, BK increased [Ca2+]ithrough activation of B2 receptors located only on the endothelium. The responses were not affected by nifedipine (10−6 M) and were smaller in a Ca2+-free medium, providing evidence that BK opens voltage-independent Ca2+ channels and mobilizes intracellular Ca2+. Thin EA differed from AA and muscular EA by a lower sensitivity to BK (EC50 = 6.95 ± 3.81 vs. 0.21 ± 0.08 and 0.18 ± 0.13 nM, respectively; P < 0.05), a higher maximal response (89 ± 5 vs. 57 ± 5 and 44 ± 7 nM; P < 0.001), and a spontaneous return to basal Ca2+ level, even in the presence of BK. Genistein (10−4 M) and herbimycin A (25 × 10−6M), specific inhibitors of tyrosine kinases, inhibited the [Ca2+]iresponses exclusively in AA. Genistein reduced the peak and plateau phases of responses by 69 ± 9 and 82 ± 6%, respectively, in a medium with Ca2+ and the peak by 48 ± 9% in a Ca2+-free medium. Similar reductions were observed with herbimycin A. These results show that dissimilar signal transduction pathways are involved in BK effects on juxtamedullary arterioles and that a tyrosine kinase activity could participate in the regulation of BK effect on AA but not on EA.

Sign in / Sign up

Export Citation Format

Share Document