• Title/Summary/Keyword: Clouds radiative forcing

Search Result 8, Processing Time 0.018 seconds

Radiative Role of Clouds on the Earth Surface Energy Balance (지표 에너지 수지에 미치는 구름의 복사 역할)

  • Hong, Sung-Chul;Chung, Ii-Ung;Kim, Hyung-Jin;Lee, Jae-Bum;Oh, Sung-Nam
    • Journal of Environmental Science International
    • /
    • v.16 no.3
    • /
    • pp.261-267
    • /
    • 2007
  • In this study, the Slab Ocean Model (SOM) is coupled with an Atmospheric General Circulation Model (AGCM) which developed in University of Kangnung based on the land surface model of Biosphere-Atmosphere Transfer Scheme (BATS). The purposes of this study are to understand radiative role of clouds considering of the atmospheric feedback, and to compare the Clouds Radiative Forcing (CRF) come from the analyses using the clear-cloud sky method and CGCM. The new CGCM was integrated by using two sets of the clouds with radiative role (EXP-A) and without radiative role (EXP-B). Clouds in this two cases show the negative effect $-26.0\;Wm^{-2}$ of difference of radiation budget at top of atmosphere (TOA). The annual global means radiation budget of this simulation at TOA is larger than the estimations ($-17.0 Wm^{-2}$) came from Earth Radiation Budget Experiment (ERBE). The work showed the surface negative effect with $-18.6 Wm^{-2}$ in the two different simulations of CRF. Otherwise, sensible heat flux in the simulation shows a great contribution with positive forcing of $+24.4 Wm^{-2}$. It is found that cooling effect to the surface temperature due to radiative role of clouds is about $7.5^{\circ}C$. From this study it could make an accurate of the different CRF estimation considering either feedback of EXP-B or not EXP-A under clear-sky and cloud-sky conditions respectively at TOA. This result clearly shows its difference of CRF $-11.1 Wm^{-2}$.

Radiative Properties of Greenhouse Gases, Aerosols and Clouds in Korea

  • Moon, Yun-Seob;Bang, So-Young;Oh, Sung-Nam
    • Proceedings of the Korean Environmental Sciences Society Conference
    • /
    • 2003.11a
    • /
    • pp.51-54
    • /
    • 2003
  • We analyzed radiative properties of aerosols, $CO^{2}$ and clouds using Optical Properties of Aerosols and Clouds(OPAC) and the Column Radiation Model (CRM). From OPAC, if the soot component is disregarded, dust-like components depict the highest extinction values in the solar spectral range and the lowest. single scattering albedoes, which are attributable to the presence of large particles. In the dust aerosol, the high absorptivity in the infrared may induce a warming of the lower atmospheric layer in the nighttime. The radiative properties of aerosols, clouds and double $CO^{2}$ using the CRM model at Seoul (37N, 127.4 E) on 3 April 2003 were calculated. The solar zenith angle is 65˚ and the surface albedo is 0.1836 during the clear day. The aerosol optical depth change 0.14 to 1.7, which is derived during Asian dust days in Korea. At this time, abedo by aerosols is considered as 0.3. In cloudy condition, the short wave cloud forcing on both the TOA and the surface is -193.89 $Wm^{-2}$ and -195.03 $Wm^{-2}$, respectively, and the long wave cloud forcing is 19.58 $Wm^{-2}$ and 62.08 $Wm^{-2}$, respectively. As a result, the net radiative cloud forcing is -174.31 $Wm^{-2}$ and -132.95 $Wm^{-2}$, respectively. We calculate also radiative heating rates by double $CO^{2}$ during the clear day. The $CO^{2}$ volumn mixing ratio is 3.55E-4.

  • PDF

Interrelationships between Sea Surface Temperatures and Clouds over the Tropical Oceans (열대 해양의 해수면온도와 구름의 상호관계)

  • 송봉근;김영섭;박경원
    • Proceedings of the KSRS Conference
    • /
    • 2001.03a
    • /
    • pp.92-97
    • /
    • 2001
  • The intra-annual and interannual variations of total, high, middle, low clouds, and cloud forcing net solar radiation flux, cloud forcing net long-wave radiation flux, and SSTs over the tropical oceans are investigated with the use of ISCP D2, NCEP/NCAR Reanalysis for January 1983-December 1993. The intra-annual variation of total cloudiness is dominated by high and middle clouds in the western Pacific and central tropical oceans, the interannual variation of total cloudiness is also dominated by high and middle clouds in the central Pacific and Atlantic. The dominant intra-annual and interannual EOFs of total cloudiness have spatially coherent link with those SSTs. For the interannual EOFs, total cloudiness and SSTs are related to E1 nino-Southern Oscillation(ENSO). The second most important intra-annual EOFs of total cloudiness are related to Inter Tropical Convergence Zone(ITCZ). The third most important intra-annual EOFs show coherent relation in the western Pacific. The correlation analysis between cloud radiative effects and SSTs show spatially coherent relation over the tropical oceans even though cloud forcing cooling effect is much higher than heating effect.

  • PDF

Measurement of Optical Properties of Ice-crystal Cloud using LIDAR System and Retrieval of Its Radiative Forcing by Radiative Transfer Model (라이다 시스템을 이용한 ice-crystal cloud의 광학적 특성 관측 및 복사 전달 모델을 통한 복사강제력 산출)

  • Noh, Young-Min;Shin, Dong-Ho;Lee, Kyung-Hwa;Muller, Detlef;Kim, Young-J.
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.25 no.5
    • /
    • pp.392-401
    • /
    • 2009
  • Ice-crystal clouds observation was conducted using a GIST/ADEMRC Multi-wavelength Raman lidar system in order to measure vertical profile and optical depth at Gwangju ($35^{\circ}$10'N, $126^{\circ}$53'E), Korea in December 2002, and March and April 2003. Ice-crystal clouds at high altitude can be distinguished from atmospheric aerosols by high depolarization ratio and high altitude. Ice-crystal clouds were observed at 5~12 km altitudes with a high depolarization ratio from 0.2 to 0.5. Optical depth of ice-crystal clouds had varied from 0.14 to 1.81. The radiative effect of observed ice-crystal cloud on climate system was estimated to be negative net flux in short wavelength (0.25~$4.0{\mu}m$) and positive net flux in short+long wavelength (0.25~$100{\mu}m$) at top of the atmosphere. Net flux by ice-crys tal cloud per unit optical depth was comparable to that of Asian dust.

Temporal Variations in Optical Properties and Direct Radiative Forcing of Different Aerosol Chemical Components in Seoul using Hourly Aerosol Sampling (서울지역 시간별 에어로솔 자료를 이용한 화학성분별 광학특성 및 직접 복사강제력의 시간 변화 분석)

  • Song, Sang-Keun;Shon, Zang-Ho
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.30 no.1
    • /
    • pp.1-17
    • /
    • 2014
  • Temporal variations of optical properties of urban aerosol in Seoul were estimated by the Optical Properties of Aerosols and Clouds (OPAC) model, based on hourly aerosol sampling data in Seoul during the year of 2010. These optical properties were then used to calculate direct radiative forcing during the study period. The optical properties and direct radiative forcing of aerosol were calculated separately for four chemical components such as water-soluble, insoluble, black carbon (BC), and sea-salt aerosols. Overall, the coefficients of absorption, scattering, and extinction, as well as aerosol optical depth (AOD) for water-soluble component predominated over three other aerosol components, except for the absorption coefficient of BC. In the urban environment (Seoul), the contribution of AOD (0.10~0.12) for the sum of OC and BC to total AODs ranged from 23% (spring) to 31% (winter). The diurnal variation of AOD for each component was high in the morning and low in the late afternoon during the most of seasons, but the high AODs at 14:00 and 15:00 LST in summer and fall, respectively. The direct negative radiative forcing of most chemical components (especially, $NO_3{^-}$ of water-soluble) was highest in January and lowest in September. Conversely, the positive radiative forcing of BC was highest in November and lowest in August due to the distribution pattern of BC concentration.

An Analysis of Aerosol Direct Radiative Forcing Using Satellite Data in East Asia During 2001-2010 (위성자료를 이용한 2001-2010년 동안의 동아시아 지역 에어로졸 직접복사강제력 분석)

  • Jeong, Ji-Hyun;Kim, Hak-Sung;Kim, Joon-Tae;Park, Yong-Pil;Choi, Hyun-Jung
    • Journal of Environmental Science International
    • /
    • v.22 no.8
    • /
    • pp.1053-1062
    • /
    • 2013
  • The shortwave aerosol direct radiative forcing (SWARF) was analyzed using the Clouds and Earth's Radiant Energy System (CERES) data in the East Asian region from 2001 to 2010. In the Yellow Sea and the Korean Peninsula, located in the leeward side of China, significantly negative high SWARF at the top of atmosphere (TOA) occurs due to the long-range transport of anthropogenic (e.g. sulphate) and natural aerosols (e.g. mineral dust) from the East Asian continent. Conversely, eastern China has much higher levels of SWARF at the surface (SFC) due to anthropogenically emitted aerosol than in the Yellow Sea and the Korean Peninsula. Since the radiative forcing of aerosols in the atmosphere are different in type, aerosol types were classified into sea salt+sulphate, smoke, sulphate and dust by using satellite data. The analysis on the SWARF by the classified aerosol types indicated that sulphate occupies a predominant portion of the atmosphere in the Yellow Sea and the Korean Peninsula in the summer. In particular, the annual averages of the summer TOA SWARF increased in the Yellow Sea and the Korean Peninsula from 2001 to 2010.

Aerosol Indirect Effect Studies derived from the Ground-based Remote Sensings (지상원격탐사를 이용한 에어러솔 간접효과 연구)

  • Kim Byung-Gon;Kwon Tae-Young
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.22 no.2
    • /
    • pp.235-247
    • /
    • 2006
  • Aerosol indirect radiative forcing of climate change is considered the most uncertain forcing of climate change over the industrial period, despite numerous studies demonstrating such modification of cloud properties and several studies quantifying resulting changes in shortwave radiative fluxes. Detection of this effect is made difficult by the large inherent variability in cloud liquid water path (LWP): the dominant controlling influence of LWP on optical depth and albedo masks any aerosol influences. Here we have used ground-based remote sensing of cloud optical depth (${\tau}_c$) by narrowband radiometry and LWP by microwave radiometry to determine the dependence of optical depth on LWP, thereby permitting examination of aerosol influence. The method is limited to complete overcast conditions with liquid-phase single layer clouds, as determined mainly by millimeter wave cloud radar. The results demonstrate substantial (factor of 2) day-to-day variation in cloud drop effective radius at the ARM Southern Great Plains site that is weakly associated with variation in aerosol loading as characterized by light-scattering coefficient at the surface. The substantial scatter suggests the importance of meteorological influences on cloud drop size as well, which should be analyzed in the further intensive studies. Meanwhile, it is notable that the decrease in cloud drop effective radius results in marked increase in cloud albedo.

Climate Influences of Galactic Cosmic Rays (GCR): Review and Implications for Research Policy (우주기원의 고에너지 입자가 기후에 미치는 영향: 연구 현황과 정책적 시사점)

  • Kim, Jiyoung;Jang, Kun-Il
    • Atmosphere
    • /
    • v.27 no.4
    • /
    • pp.499-509
    • /
    • 2017
  • Possible links among cosmic ray, cloud, and climate have scientific uncertainties. The reputed topics have been highly controversial during several decades. A link between the atmospheric ionization by galactic cosmic rays (GCR), which is modulated by solar activities, and global cloud cover was firstly proposed in 1997. Some researchers suggested that the GCR can stimulate the formation of cloud condensation nuclei (CCN) in the atmosphere, and then the higher CCN concentrations may lead to an increase of cloud cover, resulting in a cooling of the Earth's climate, and vise versa. The CLOUD (Cosmic leaving outdoor droplets) experiment was designed to study the effect of GCR on the formation of atmospheric aerosols and clouds under precisely controlled laboratory conditions. A state-of-the-art chamber experiment has greatly advanced our scientific understanding of the aerosol formation in early stage and its nucleation processes if the GCR effect is considered or not. Many studies on the climate-GCR (or space weather) connection including the CLOUD experiment have been carried out during the several decades. Although it may not be easy to clarify the physical connection, the recent scientific approaches such as the laboratory experiments or modeling studies give some implications that the research definitively contributed to reduce the scientific uncertainties of natural and anthropogenic aerosol radiative forcing as well as to better understand the formation processes of fine particulate matters as an important parameter of air quality forecast.