구름과 에어로솔의 혼재시 에어로솔의 광학특성이 상향 단파 복사에 미치는 영향

이권호 ( Kwon-ho Lee ) 대한원격탐사학회 2017 大韓遠隔探査學會誌 Vol.33 No.3

에어로솔의 광학특성과 연직고도는 태양 복사의 반사와 흡수과정을 통하여 지구복사수지에 영향을 미치게 된다. 본 연구에서는 복사전달모델과 위성관측자료를 이용하여 동북아시아 지역에서 구름의 존재 시에어로솔 층에 의한 복사특성을 분석하였다. 복사전달 모의 결과는 구름이 하부에 존재하는 경우에 에어로솔 층의 고도가 높아짐에 따라 대기 온난화 효과가 증가하였다. 이러한 관계는 에어로솔의 광 흡수성이 커질수록, 지표 반사도가 증가할수록 비례하는 경향을 나타내었다. 그리고 연구대상지역 (20-50 °N, 110-140 °E)에서 주요 에어로솔 이벤트 사례에 대하여, UV Absorbing Aerosol Index (AAI) derived from Total Ozone Mapping Spectrometer (TOMS), cloud parameters derived from the Moderate Resolution Imaging Spectro-radiometer (MODIS), with Upward Shortwave Flux (USF) Clouds and the Earth`s Radiant Energy System (CERES) 위성관측자료를 이용하여 광 흡수성 에어로솔에 의한 영향을 정량적으로 분석하였다. 각 사례에 대한 평균적인 복사효과는 약 6 - 26 %에 해당하는 상향 단파 복사량의 감쇄효과가 나타났다. 이러한 결과는 에어로솔에 의한 직접효과와 간접효과를 정량화 하기 위한 중요성을 설명해 준다. Aerosol optical properties as well as vertical location of layer can alter the radiative balance of the Earth by reflecting and absorbing solar radiation. In this study, radiative transfer model (RTM) and satellite-based analysis have been used to quantify the top-of-atmosphere (TOA) radiative effect of aerosol layers in the cloudy atmosphere of the northeast Asia. RTM simulation results show that the atmospheric warming effect of aerosols increases with their height in the presence of underlying cloud layer. This relationship is higher for stronger absorbing aerosols and higher surface albedo condition. Over study region (20-50 °N, 110-140 °E) and aerosol event cases, it is possible to qualitatively identify absorbing aerosol effects in the presence of clouds by combining the UV Absorbing Aerosol Index (AAI) derived from Total Ozone Mapping Spectrometer (TOMS), cloud parameters derived from the Moderate Resolution Imaging Spectro-radiometer (MODIS), with TOA Upward Shortwave Flux (USF) from the Clouds and the Earth`s Radiant Energy System (CERES). As the regional-mean radiative effect of aerosols, 6 - 26 % lower the USF between aerosols and cloud cover is taken into account. These results demonstrate the importance of estimation for the accurate quantification of aerosol`s direct and indirect effect.

Asymmetry of Cloud Vertical Structures and Associated Radiative Effects in Typhoon over the Northwest Pacific Based on CloudSat Tropical Cyclone Dataset

Yan Yafei,Tan Jianguo,Cui Linli,Yu Wei,Hu Yan 한국기상학회 2020 Asia-Pacific Journal of Atmospheric Sciences Vol.56 No.4

The clouds’ macro-, microphysical vertical structures and radiative effects in 4 shear-relative quadrants of typhoon over the northwest Pacific during development, maturity and extinction stages are studied based on CloudSat Tropical Cyclone dataset and China Meteorological Administration tropical cyclone dataset from 2nd June 2006 to 31th December 2015. The typhoon cloud is in an asymmetric “mushroom” shape, with the downshear quadrants (in particular of the downshear left quadrant (DL)) have denser clouds than the upshear quadrants. Cloud ice water content mainly distributes near typhoon center with wide vertical range (6–17 km). A large number of ice particles with small sizes are gathering in high levels, while small amount of ice particles with large sizes are gathering in low levels. As typhoon matures, the number concentration and size of cloud ice particles in inner ring increases, especially in the DL quadrant; while in the upshear left (UL) quadrant, a larger amount of ice particles with bigger sizes are transport to high levels (above 16 km) by deeper convection near storm center. The shortwave (longwave) cloud radiative effects (CRE) is mainly heating (cooling) upper layer atmosphere between 10 km and 17 km (between 14 km and 17 km), and the net CRE on atmosphere is heating almost at any levels in typhoon. The strongest heating of shortwave CRE and net CRE, as well as the strongest cooling of longwave CRE are in the DL quadrant at development stage and in the UL quadrant at maturity stage in inner core of storms. The existences of typhoon clouds mainly decrease solar radiation penetrating to the earth surface and increase longwave radiation absorbed by the whole atmosphere in typhoon’s inner core, and they are generally stronger in downshear (especially in DL) quadrants, except the maturity stage when the UL quadrant performs the strongest shortwave CRE on the surface and longwave CRE on the atmosphere in typhoon’s inner core.

Aerosol radiative effects on mesoscale cloud–precipitation variables over Northeast Asia during the MAPS-Seoul 2015 campaign

Park, Shin-Young,Lee, Hyo-Jung,Kang, Jeong-Eon,Lee, Taehyoung,Kim, Cheol-Hee Elsevier 2018 Atmospheric environment Vol.172 No.-

<P>The online model, Weather Research and Forecasting Model with Chemistry (WRF-Chem) is employed to interpret the effects of aerosol-cloud-precipitation interaction on mesoscale meteorological fields over Northeast Asia during the Megacity Air Pollution Study-Seoul (MAPS-Seoul) 2015 campaign. The MAPS-Seoul campaign is a pre-campaign of the Korea-United States Air Quality (KORUS-AQ) campaign conducted over the Korean Peninsula. We validated the WRF-Chem simulations during the campaign period, and analyzed aerosol-warm cloud interactions by diagnosing both aerosol direct, indirect, and total effects. The results demonstrated that aerosol directly decreased downward shortwave radiation up to -44% (-282 W m(-2)) for this period and subsequently increased downward longwave radiation up to + 15% (similar to 52 W m(-2)) in the presence of low-level clouds along the thematic area. Aerosol increased cloud fraction indirectly up to similar to 24% with the increases of both liquid water path and the droplet number mixing ratio. Precipitation properties were altered both directly and indirectly. Direct effects simply changed cloud-precipitation quantities via simple updraft process associated with perturbed radiation and temperature, while indirect effects mainly suppressed precipitation, but sometimes increased precipitation in the higher relative humidity atmosphere or near vapor-saturated condition. The total aerosol effects caused a time lag of the precipitation rate with the delayed onset time of up to 9 h. This implies the importance of aerosol effects in improving mesoscale precipitation rate prediction in the online approach in the presence of non-linear warm cloud.</P>

The Iris Effect: A Review

Richard S. Lindzen,최용상 한국기상학회 2022 Asia-Pacific Journal of Atmospheric Sciences Vol.58 No.1

This study reviews the research of the past 20-years on the role of anvil cirrus in the Earth’s climate – research initiated by Lindzen et al. (Bull. Am. Meteor. Soc. 82:417-432, 2001). The original study suggested that the anvil cirrus would shrink with warming, which was estimated to induce longwave cooling for the Earth. This is referred to as the iris effect since the areal change hypothetically resembles the light control by the human eye’s iris. If the effect is strong enough, it exerts a significant negative climate feedback which stabilizes tropical temperatures and limits climate sensitivity. Initial responses to Lindzen et al. (Bull. Am. Meteor. Soc. 82:417-432, 2001) denied the existence and effectiveness of the iris effect. Assessment of the debatable issues in these responses will be presented later in this review paper. At this point, the strong areal reduction of cirrus with warming appears very clearly in both climate models and satellite observations. Current studies found that the iris effect may not only come from the decreased cirrus outflow due to increased precipitation efficiency, but also from concentration of cumulus cores over warmer areas (the so-called aggregation effect). Yet, different opinions remain as to the radiative effect of cirrus clouds participating in the iris effect. For the iris effect to be most important, it must involve cirrus clouds that are not as opaque for visible radiation as they are for infrared radiation. However, current climate models often simulate cirrus clouds that are opaque in both visible and infrared radiation. This issue requires thorough examination as it seems to be opposed to conventional wisdom based on explicit observations. This paper was written in the hope of stimulating more effort to carefully evaluate these important issues.

Cloud Radiative Effects and the Pacific Decadal Oscillation: Insights from a Cloud-Locking Experiment

Chiyoung Kim,Hanjun Kim,Sarah M. Kang 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.4

Tropical upper-level cloud radiative effect in the framework of radiative-convective equilibrium model

Hyoji Kang,Yong-Sang Choi 한국기상학회 2022 한국기상학회 학술대회 논문집 Vol.2022 No.10

Factors determining tropical upper-level cloud radiative effect using a radiative-convective equilibrium model

Hyoji Kang,Yong-Sang Choi,Jonathan H. Jiang 한국기상학회 2024 한국기상학회 학술대회 논문집 Vol.2024 No.4

Quantifying the Shortwave Cloud Radiative Effects in Arctic Climate Change Projections

Doyeon Kim,Sarah M. Kang,Hanjun Kim 한국기상학회 2021 한국기상학회 학술대회 논문집 Vol.2021 No.10

Arctic summer sea ice has declined rapidly to extensive change of surface shortwave radiation under global warming. In particular, cloud radiative effect (CRE) is important on the Arctic surface radiation budget and the major source of inter-model spread in predictions of Arctic climate. Using CMIP5 (Coupled Model Intercomparison Project) and CMIP6 climate models, we decompose the shortwave CRE on the Arctic surface and analyze inter-model differences. This is done by taking into account the fact that the response of shortwave CRE to Arctic warming is influenced by change in surface albedo, cloud amount, and cloud microphysics. In summer, reduction in surface albedo is directly linked to strong negative shortwave CRE (120% of this change in the net shortwave CRE) and explains the extensive model differences. Arctic clouds may hamper the surface albedo feedback by (1) reducing downward shortwave fluxes with reflecting the incoming solar radiation and (2) reflecting diminished upward shortwave fluxes from the less reflective surface. Increased (decreased) cloud amount and cloud water is shown to be less (more) incoming shortwave fluxes at the surface, but not a dominating factor to the Arctic surface radiation budget and its inter-model variation. As a results, this study helps to decompose the each CRE feedback at the Arctic surface and emphasizes that it is critical for the prediction of shortwave CRE on the Arctic surface to consider not only the cloud amount, but also its microphysics and surface albedo.

Decomposition of Arctic shortwave cloud radiative effects under global warming

Doyeon Kim,Sarah M.Kang,Hanjun Kim 한국기상학회 2022 한국기상학회 학술대회 논문집 Vol.2022 No.4

Intercomparison of satellite remote-sensed cloud phase composition data and its implication in uncertainty of cloud radiative effect

Hyoji Kang(강효지),Yong-Sang Choi,Hye-Sil Kim 한국기상학회 2019 한국기상학회 학술대회 논문집 Vol.2019 No.05