The radiation budget of the atmosphere over the Arctic compiled from the ISCCP-FD data sets (preliminary results)

The technological advancements of the past two to three decades enabled the establishment of space-borne observational systems to measure worldwide clouds and related radiation fields at the top of the atmosphere. This data when combined with further information on the thermodynamic state of the atmosphere and ground allows for estimates of the radiation budget at ground and within the atmosphere. This information is urgently required to calibrate the output of climate models and to understand current changes in the climate system. Results of the International Satellite Cloud Climatology Project (ISCCP) are here presented and compared with another but similar data set of the Global Energy and Water Cycle Experiment (GEWEX-SRB) and with ground-based measurements. This data describes details in space and time of the variability of radiation budget parameters at the surface and at the top of the atmosphere over the entire globe. Over the Arctic ice fields-our studies concern areas poleward of about 60°N-considerable uncertainties of more than 20Wm^(-2) still exist in both the long-wave and short-wave budget components at ground

Case study on microphysical properties of boundary layer mixed-phase cloud observed at Ny-Ålesund, Svalbard: Observed cloud microphysics and calculated optical properties on 9 June 2011

AbstractCloud radiation interactions are important in the global climate system. However, an understanding of mixed-phase boundary layer clouds in the Arctic remains poor. During May–June 2011, ground-based in situ measurements were made at Zeppelin Station, operated by the Norwegian Polar Institute (altitude 474 m) in Ny-Ålesund (78.9°N, 11.9°E), Svalbard. The instruments used comprised a Cloud, Aerosol and Precipitation Spectrometer (CAPS), and a Cloud Particle Microscope imager. The CAPS incorporated a Cloud and Aerosol Spectrometer and Cloud Imaging Probe (CIP). During the observation period, clouds associated with cyclonic disturbances and those associated with outbreaks of westerly cold air masses from the sea were observed. Atmospheric temperature during all measurements ranged from 0 to −5 °C. In every case, columns were the major type of ice particle measured by the CAPS–CIP. Cloud microphysical properties were observed continuously on 9 June 2011. Size spectra, liquid/ice water content, and particle effective size changed depending on progress stages. Based on the observed microphysics, optical properties were calculated and investigated. Optical properties were determined mainly by those of liquid water particles, even during periods when the relative contribution of ice particles to total water content was at the maximum. It was confirmed that the wavelength region of 1.6 and 2.2 μm can be used in remote sensing. This study shows that it is possible to measure detailed changes of cloud properties in the Arctic region by using instruments installed at a ground-based mountain station

Seasonal variation of chemical composition of aerosols at Syowa Station, Antarctica in 2001

Antarctic aerosols collected at Syowa Station in 2001 were analyzed to investigate their seasonal variations and long-range transport of anthropogenic aerosols. The measured chemical species were elemental carbon(E.C.) and organic carbon(O.C.) using a combustion technique, SO_4^, NO_3^-, Cl^-, Na^+, NH_4^+, K^+, Ca^ and Mg^ using ion chromatographs, and metals such as Al, V, Cr, Mn, Fe, Co, Ni, Zn and Pb using an inductively coupled plasma mass spectrometer. Total mass concentration of aerosols ranged from 0.366 to 2.72μg/m^3 and increased from winter to spring. The NO_3^- concentration was lower than 0.01μg/m^3 in March-July; in contrast, it was higher than 0.02μg/m^3 in August-November. Concentration of elemental carbon was relatively low in April-June and was high in March, October and November. In October and November, NO_3^- concentration was also high. Therefore, the air mass was possibly affected by biomass burning. The concentration of SO_4^- was low around 0.02μg/m^3 in May-July, and it increased to higher than 0.1μg/m^3 in August-December. The concentrations of Al, V, Co, Ni and Pb were sometimes lower than the detection limits. Nevertheless, spikes of the highest concentrations of V, Cr, Fe, Co, Ni, Zn and Pb were recorded in August-October, while V and Fe showed second spikes in March. The enrichment factors of Cr, Ni, Zn and Pb were high during 13-20 September and 12-22 October. The E.C. concentrations in these periods were also relatively higher than before and after the sampling periods. Moreover, blizzards occurred in these periods

Arctic experiment for ICESat/GLAS ground validation with a Micro-Pulse Lidar at Ny-Alesund, Svalbard

A Micro-Pulse Lidar (MPL) has been operated in Ny-Alesund, Svalbard (78°55\u27N, 11°56\u27E, 0.010 km msl) to collect zenith scattering profiles of aerosols and clouds since 1998. The Ice, Cloud, and land Elevation Satellite (ICESat) was launched by NASA in January 2003 with a single payload instrument, the Geoscience Laser Altimeter System (GLAS), designed for active remote sensing of the atmosphere as well as ice sheet height change in the cryosphere. Overpass experiments for ground validation of the ICESat/GLAS atmospheric measurements were performed in 2003 and 2004. Two case-studies comparing lidar measurements from space-borne GLAS and ground-based MPL in the Arctic are described here for a geometrically thick but optically thin cloud and a geometrically thin but optically thick cloud. The result validates the basic procedure for cloud signal processing and attenuation correction of the GLAS data

Improvement of shipborne sky radiometer and its demonstration aboard the Antarctic research vessel Shirase

動揺する船上においても太陽直達光を観測できるように，船舶用スカイラジオメータの太陽追尾性能を改良した．改良点は，太陽追尾精度の向上，測器視野角の拡大，太陽追尾速度の迅速化および測定手法の改良である．改良後の装置を用いて，第51次および第52次日本南極地域観測隊の本観測時に，南極観測船「しらせ」船上において太陽直達光および天空輝度分布を測定し，動揺した船上での直達光観測に成功した．直達光から算出された波長500nm における大気エアロゾルの光学的厚さは0.01-0.34であり，東南アジアおよび春季の西太平洋上で高い値を示した．オングストローム指数は－0.06～2.00の範囲であり，東南アジアおよびシドニー付近で最大を示した．今後，船舶用スカイラジオメータが，海洋上の大気エアロゾルに関する知見を深めると期待される．The sun-tracking performance of a shipborne sky radiometer was improved to attain accurate aerosol optical thickness (AOT) from direct solar measurements on a pitching and rolling vessel. Improvements were made in the accuracy of sun-pointing measurements, field-of-view expansion, sun-tracking speed, and measurement method. Radiometric measurements of direct solar and sky brightness distribution were performed using the shipborne sky radiometer onboard the Antarctic research vessel (R/V) Shirase during JARE-51 (2009-2010) and JARE-52 (2010-2011). The temporal variation of signal intensity measured by the radiometer under cloudless conditions was smooth, demonstrating that the radiometer could measure direct sunlight onboard the R/V. AOT at 500 nm ranged from 0.01 to 0.34, and values over Southeast Asia and over the western Pacific Ocean in spring were higher than those over other regions. The Angstrom exponent ranged from －0.06 to 2.00, and values over Southeast Asia and off the coast near Sydney were the highest. The improved shipborne sky radiometer will contribute to a good understanding of the nature of aerosols over the ocean

Field experiment of mixed-phase clouds with Cloud Particle Microscope

第2回極域科学シンポジウム/第34回気水圏シンポジウム 11月14日（月） 統計数理研究所 セミナー室

Aerosol nucleation observed in JARE51

第2回極域科学シンポジウム　共通セッション「海氷圏の生物地球化学」 11月16日（水） 統計数理研究所 3階リフレッシュフロ

南極昭和基地及び北極ニーオルスンにおける雲の変動

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　統計数理研究所 セミナー室2（D304

Interannual variability of aerosols determined from a sky radiometer observation onboard Shirase

第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月30日（金） 国立国語研究所 ２階多目的

Variation of cloud fraction during intensive observation period in the springtime of 2011 at Ny-Ålesund

第2回極域科学シンポジウム/第34回気水圏シンポジウム 11月15日（火） 統計数理研究所 3階リフレッシュフロ