AAS01-01

会場:301B

時間:5 月 27 日 14:15-14:45

Lidar Measurements of Atmospheric Column CO2 from Regional to Global Scales
Lidar Measurements of Atmospheric Column CO2 from Regional to Global Scales
LIN, Bing1∗
LIN, Bing1∗
11NASA Langley Research CenterNASA Langley Research Center

Atmospheric CO2 is a critical forcing for the earth’s climate and the knowledge on its distributions and variations influencespredictions of the Earth’s future climate. Large uncertainties in the predictions persist due to limited observations. This study
uses the airborne Intensity-Modulated Continuous-Wave (IM-CW) lidar developed at NASA Langley Research Center to measureregional atmospheric CO2 spatiotemporal variations. Further lidar development and demonstration will provide the capabilityof global atmospheric CO2 estimations from space, which will significantly advances our knowledge on atmospheric CO2 andreduce the uncertainties in the predictions of future climate.
In this presentation, atmospheric CO2 column measurements from airborne flight campaigns and lidar system simulations forspace missions will be discussed. Data analysis shows that airborne lidar CO2 column measurements over desert and vegetatedsurfaces agree well with in-situ measurements. A measurement precision of ˜0.3 ppmv for a 10-s average over these surfaces hasalso been achieved. Generally, airborne flight campaigns have demonstrated that the column CO2 measurements of the current
IM-CW lidar systems meet the accuracy and precision requirements of atmospheric CO2 sciences. Furthermore, analyses ofspace CO2 measurements shows that the current IM-CW lidar technology and approach will enable space missions to achieve
their science goals.
キーワード: atmospheric CO2, lidar measurements, regional, global
Keywords: atmospheric CO2, lidar measurements, regional, global

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AAS01-02

会場:301B

時間:5 月 27 日 14:45-15:15

Technical approaches for future active optical remote sensing
Technical approaches for future active optical remote sensing
石井 昌憲 1∗ ; Sato Atsushi2 ; Baron Philippe1 ; Mizutani Kohei1 ; Iwai Hironari1 ; SATO Masaki6 ;OKAMOTO Kozo4 ; Oki Riko3 ; IWASAKI Toshiki7 ; NISHIZAWA Tomoaki5 ; Aoki Makoto1 ; Yasui Motoaki1 ;Ochiai Satoshi1
ISHII, Shoken1∗ ; SATO, Atsuhi2 ; BARON, Philippe1 ; MIZUTANI, Kohei1 ; IWAI, Hironari1 ;SATO, Masaki6 ; OKAMOTO, Kozo4 ; OKI, Riko3 ; IWASAKI, Toshiki7 ; NISHIZAWA, Tomoaki5 ;AOKI, Makoto1 ; YASUI, Motoaki1 ; OCHIAI, Satohi1
1National Institute of Information and Communications Technology, 2 Tohoku Institute of Technology, 3 Japan Aerospace Exploration Agency, 4 Meteorological Research Institute, 5 National Institute for Environmental Studies, 6 The University of Tokyo,
7Tohoku University
1National Institute of Information and Communications Technology, 2 Tohoku Institute of Technology, 3 Japan Aerospace Exploration Agency, 4 Meteorological Research Institute, 5 National Institute for Environmental Studies, 6 The University of Tokyo,
7Tohoku University
Lidar is a unique active optical remote sensing technique, which can detect very small particles such as molecules, gas andparticulate aerosols, clouds. Lidar can also measure range, wind speed, concentration of atmospheric constituents such as CO2,water vapor and so on. Communication Research Laboratory (CRL: former institute of NICT) proposed development of thespace-borne coherent DWL as a candidate of the earth observation missions on the International Space Station (ISS)-JapaneseExperimental Module (JEM) in 1997, which was called JEM-CDL. NICT started studies on feasibility of JEM-CDL under thesupport of the Phase II studies of the Ground Research Announcement of the National Space Development Agency (former institute of JAXA). NICT studied 2-μ m laser technologies for the JEM-CDL during 6 years from FY2000 to FY2005 and develop a2-μ m laser with a high pulse-energy of 460 mJ operating at 10 Hz. NICT developed a 2-μ m conductively-cooled laser-diodepumped single-frequency Q-switched solid-state laser as a second-generation laser system. NICT developed a ground-based
2-μ m coherent differential absorption and Doppler wind lidar for CO2 and wind measurements. DIfferential Absorption Lidar (DIAL) is more complicated than passive sensor, it has the potential advantage of measuring concentration of atmosphericconstituents during nighttime. CO2 sources and sinks are located near the earth s surface. Since 2-μ m spectral region has sensitivity close to the surface higher than 1.6-μ m spectral region, a 2-μ m integrated path differential absorption (IPDA) lidar isone of the promising space-borne active optical remote sensors. The coherent Doppler Wind Lidar (DWL) is also a complicatedsystem but can measure Doppler wind speed with a high accuracy during daytime as well as nighttime. Although space-borne
passive sensor needs scattering objects (water vapor, cloud), coherent DWL can provide a wind profile even clear sky condition.
A combination of CO2 and wind measurements would facilitate better understandings of the carbon cycle on various temporaland spatial scales. Space-borne lidar can provide only profile data in a straight line. A synergy measurement of space-borne lidar
and other technique would be important and valuable. NICT conducts studies on feasibility for a space-borne Doppler Wind lidar
with JAXA, Tohoku University, the University of Tokyo, Meteorological Research Institute, and other institutes. NICT will starta new middle-term project in 2016. In this paper, we describe a future space-borne Doppler wind lidar and conceptual idea forcarbon cycle lidar measurement.
キーワード: Active remote sennsing, Space-bonre, lidar, Doppler wind lidar, Doppler wind lidar
Keywords: Active remote sennsing, Space-bonre, lidar, Wind, Greenhouse gas

1/1AAS01-03

会場:301B

時間:5 月 27 日 15:15-15:30

Atmospheric Gravity Waves: MST Radars and Sondes
Atmospheric Gravity Waves: MST Radars and Sondes
KANTHA, Lakshmi1∗ ; MIXA, Tyler1 ; HASHIGUCHI, Hiroyuki2 ; TSUDA, Toshitaka2 ; RATNAM, Venkat3 ;JAYARAMAN, A3
KANTHA, Lakshmi1∗ ; MIXA, Tyler1 ; HASHIGUCHI, Hiroyuki2 ; TSUDA, Toshitaka2 ; RATNAM, Venkat3 ;JAYARAMAN, A311

University of Colorado, Boulder, USA, 2 RISH, Kyoto University, Japan, 3 NARL, Gadanki, India
University of Colorado, Boulder, USA, 2 RISH, Kyoto University, Japan, 3 NARL, Gadanki, India

MST radars have proved to be extremely useful in monitoring atmospheric gravity waves and understanding their role in themiddle and upper atmosphere dynamics. However, there are only a few such radars around the world, making routine monitoringof gravity waves in the global atmosphere impossible. Using sondes to extract wave information such as the momentum flux
would help monitor and study gravity waves in the troposphere and the lower stratosphere, provided the method can be demonstrated to yield realistic results. As a sonde ascends, its vertical velocity is modulated by gravity waves so that, in principle, it
should be possible to extract wave properties such as the energy density and momentum flux. However, the aerodynamics of theflow around the balloon complicates the sonde vertical motion. The Reynolds number of the flow is around the transitional value
so that transition of the boundary layer on the forward hemisphere from laminar to turbulent can change the wake size and hence
the drag in an unpredictable fashion, affecting the vertical velocity. We have modeled the behavior of the balloon assuming it tobe elastic so that the sonde vertical velocity can be modeled and the transition from low drag to high drag assessed. The extensive
sonde dataset collected during the 2005 CPEA II campaign at the Koto Tabang Equatorial Radar facility has been used to explore
the technique. The vertical velocity fluctuations resulting from the model have been used to estimate atmospheric gravity wave
properties at the radar site during the month-long campaign.
Proper validation of sonde-extracted gravity wave properties requires comparison with another independent, reliable and simultaneous set of measurements. MST radars, being the gold standard for gravity wave studies, provide such an opportunity. Atthe NARL MST radar facility in Gadanki, India, there exist radar data obtained during some sonde launches. We have used thesedata to compare wave properties extracted from sondes with those extracted from radar horizontal and vertical wind velocity
measurements. We find the sonde provides results consistent with radar measurements, thus providing more confidence in theutility of the technique for studying gravity waves in the global stratosphere. We will present results of these comparisons anddiscuss their potential utility and some unresolved issues.

キーワード: MST radar, Radiosonde, Atmospheric gravity waves
Keywords: MST radar, Radiosonde, Atmospheric gravity waves

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AAS01-04

会場:301B

時間:5 月 27 日 15:30-15:45

Changes of Arctic Clouds and Its Implications
Changes of Arctic Clouds and Its Implications
Yongxiang Hu1∗
YONGXIANG, Hu1∗
11

NASA Langley Research CenterNASA Langley Research Center

There has been studies (e.g., Schweiger, 2004) suggest significant increase of Arctic clouds during the last three decades,
especially in the western Arctic region. Such studies are based on passive remote sensing that are not highly reliable due tothe lack of contrasts in temperature and reflectance between clouds and snow/ice surfaces. Changes in the Arctic clouds can beevaluated more accurately using the space-based lidar measurements from CALIPSO during the last nine years since CALIPSO
can provide much more accurate detection and classification of both water and ice clouds in the Arctic.
Time series of Arctic cloud properties (e.g., cloud fraction, cloud thermodynamic phase, water cloud depolarization ratio anddroplet number concentration) from CALIPSO data are analyzed in this study. This study reveals the changes in both cloud
fraction and cloud microphysical properties during the last nine years when CALIPSO data are available. We will evaluate thechanges in Arctic cloud fraction and cloud microphysical properties, their seasonal and spatial characteristics and the potential
impact on the energy budget and the climate of the Arctic.
キーワード: lidar, arctic, clouds
Keywords: lidar, arctic, clouds

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AAS01-05

会場:301B

時間:5 月 27 日 16:15-16:45

ひまわり８号のデータを用いた氷雲の解析
Ice cloud analysis using Himawari-8 data
岩渕 弘信 1∗ ; 所 悠香 1 ; 齊藤 雅典 1 ; Putri Nurfiena Sagita1 ; 片桐 秀一郎 1 ; 関口 美保 2
IWABUCHI, Hironobu1∗ ; TOKORO, Yuka1 ; SAITO, Masanori1 ; PUTRI, Nurfiena sagita1 ;KATAGIRI, Shuichiro1 ; SEKIGUCHI, Miho2
11

東北大学大学院理学研究科, 2 東京海洋大学
Tohoku University, 2 Tokyo University of Marine Science and Technology

The Himawari-8 satellite was launched in October 2014 and carries the Advanced Himawari Imager (AHI) that has 16 spectral
bands in visible to thermal infrared spectra. Spatial resolution and observation frequency have been significantly improved. Ninebands are in the thermal infrared at 6?13.5 micron wavelengths. This study aims at obtaining optical and microphysical propertiesof ice cloud, and we are developing a cloud analysis system that uses the thermal infrared bands of the AHI. Our group has beenstudied ice cloud properties by using three bands of 8.5-, 11- and 12-micron of MODIS onboard the Aqua satellite (Iwabuchi etal., 2014). The cloud top temperature was obtained from the MODIS operational product and used as a priori for inversion. To
extend the retrieval method to the AHI, we have modified the method to use multiple bands including the CO2 and water vapor
absorption bands.
First we have developed a forward model that computes brightness temperatures and its partial derivatives with respect toseveral variables. The input data are atmospheric temperature and humidity profile and surface properties. The radiative transfer
calculation is made at only a single wavelength band for each sensor band, using the correlated-k distribution (CKD) method(Sekiguchi & Nakajima, 2008) with several quadrature points. Optical properties of water droplets are computed by the LorenzMie theory, and those of ice particles are obtained from a database made by Yang et al. (2013). Ice cloud habit models include
hexagonal column and plate, and the General Habit Mix (GHM) model (Cole et al., 2013) with different degrees of surface
roughness. Double-layer clouds are modeled, and radiative transfer is solved by the two-stream approximation. Brightness temperature biases due to model approximation are removed by empirical formulae.
Absorption by ice particles is stronger at wavelengths longer than 10 micron. As suggested by prior studies, a combinationof multiple bands in the window region of 8?13 micron wavelengths allows inferring effective particle size of ice cloud. Ice
particle habits do not significantly affect the brightness temperatures, but water phase (liquid/ice) is moderately important tospectral differences in brightness temperatures. Measurements are sensitive to ice cloud with cloud optical thickness of 0.05?12and effective particle radius of 2?100 micron. Top pressure of lower cloud in multi-layer cloud column can be retrieved if theupper cloud optical thickness is less than about 5.
Background surface and atmospheric data needed for the cloud analysis are interpolated spatially and temporally from MODIS
products and MERRA reanalysis. The optimal estimation method (Rodgers, 2000) is used to infer cloud properties including cloud water path, effective particle radius, cloud-top pressure, and background surface temperature in single-layer cloudcases. Top-pressure of lower cloud is inferred in multi-layer cloud cases, instead of background surface temperature. Measurement?model biases due to errors in atmospheric data and model approximations and assumptions are evaluated by comparing
to simulated and measured brightness temperatures. The biases are removed, and remaining errors are evaluated for use in the
optimal estimation. Initial test analysis will be presented in the presentation.

キーワード: ひまわり８号, 氷雲
Keywords: Himawari-8, ice cloud

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AAS01-06

会場:301B

時間:5 月 27 日 16:45-17:15

Computation of surface irradiances using satellite observations
Computation of surface irradiances using satellite observationsKATO, Seiji1∗ ; LOEB, Norman1 ; ROSE, Fred2 ; RUTAN, David2 ; DOELLING, David1 ;RADKEVICH, Alexander2 ; HAM, Seung-hee2
KATO, Seiji1∗ ; LOEB, Norman1 ; ROSE, Fred2 ; RUTAN, David2 ; DOELLING, David1 ;RADKEVICH, Alexander2 ; HAM, Seung-hee2
11NASA Langley Research Center, 2 Science System & Applications Inc.
NASA Langley Research Center, 2 Science System & Applications Inc.

Understanding the surface radiation budget is important for several reasons. At the global and large temporal scales, it should
balance with the sum of surface latent and sensible heat fluxes and ocean heating. At regional scales, it is an indispensableboundary condition for ocean or snow models or any other models that need energy input to the surface. NASA’s Clouds and theEarth’s Radiant Energy System (CERES) project provides surface irradiance data products for a range of temporal and spatialscales computed using a radiative transfer model initialized using satellite-derived cloud and aerosol properties. Other inputs tothe radiative transfer model include temperature and humidity profiles from NASA Global Modeling and Assimilation Office’s(GMAO) reanalysis. The CERES team uses more than 80 surface observation sites located over land and ocean to evaluate
computed irradiances. When computed monthly 1degree by 1 degree gridded mean downward irradiances are compared with 10years of observed irradiances, the bias averaged over all land and ocean sites are, respectively, -1.7 Wm−2 and 4.7 Wm−2 forshortwave and -1.0 Wm−2 and -2.0 Wm−2 for longwave. The shortwave agreement is significantly better than other satellitebased surface irradiance products. One of reasons for the better agreement is careful treatment of diurnal cycle of clouds bymerging 3-hourly geostationary satellite-derived cloud properties. In addition, computed surface irradiance variability shows aremarkable agreement with observed variability. However, these data sets have their shortcomings. The uncertainty in nighttime
surface longwave irradiance over polar regions is larger than that of other regions primarily due to the difficulty of cloud detection
and large uncertainties in skin temperature and near-surface temperature and humidity. The large uncertainty in polar region
surface irradiances hampers, for example, investigation of surface radiation budget changes in response to changes in sea ice
extent. In this presentation, we present an evaluation of the current CERES products and discuss ways these products can be
improved in the future.
キーワード: surface radiation budget, climate data record
Keywords: surface radiation budget, climate data record

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AAS01-07

会場:301B

時間:5 月 27 日 17:15-17:30

水雲特性の違いに伴う 94GHz レーダ反射率の頻度分布の対応
Distributional correspondence of 94-GHz radar reflectivity with the variation in water
cloud properties
Kawamoto Kazuaki1∗ ; 鈴木 健太郎 2
KAWAMOTO, Kazuaki1∗ ; SUZUKI, Kentaroh2
11

長崎大学大学院 水産・環境科学総合研究科, 2 米国航空宇宙局ジェット推進研究所
Graduate School Fisheries Science and Environmental Studies, Nagasaki University, 2 NASA Jet Propulsion Laboratory

This paper studied the behavior of 94-GHz radar reflectivity (Ze) with variation in the properties of low-level water clouds,
such as the effective droplet radius (re), geometrical thickness (Dcld), and liquid water path (LWP), over the northwest Pacificand China. The changes in the distribution of maxZe (the largest Ze within a cloud layer) were examined in terms of variation in
the cloud parameters such as small, mid and large categories. While maxZe had monomodal distributions regarding variation inre and Dcld, that appeared bimodal in the small category of LWP. It was confirmed that the small category of LWP contained both
non-precipitating clouds in the incipient stage and raining clouds in the dissipating stage. Next, optically-measured particle size
was combined with LWP derived from the microwave measurement to classify the precipitation type. Applying maxZe and Dcld
to the analysis of classified precipitation types corroborated the importance of Dcld for examining the occurrence of precipitation.
Finally, the position of maxZe relative to the cloud top was investigated using a measure of the probability of precipitation (POP)according to variation in re. The results showed that the Pacific and China had ’bow’ and ’funnel’ shapes, respectively. The
emergence of these shapes according to the variation in re was interpreted as the enhancement of Ze due to droplet collisional
growth and the attenuation of Ze by the presence of large particles. Furthermore, a detailed analysis of smaller particles (<10micron in radius) reinforced the idea of rapid, efficient particle growth in the lower part of the cloud.
キーワード: CloudSat, レーダ反射率, 雲物理, エアロゾル, 降雨
Keywords: CloudSat, Radar reflectivity, cloud physics, aerosol, precipitation

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AAS01-08

会場:301B

時間:5 月 27 日 17:30-17:45

Detecting Super-thin Clouds with Polarized Sunlight
Detecting Super-thin Clouds with Polarized Sunlight
SUN, Wenbo1∗
SUN, Wenbo1∗
11

Science Systems and Applications, Inc., Hampton, VA 23666, USA.
Science Systems and Applications, Inc., Hampton, VA 23666, USA.

Super-thin clouds exist globally but are extremely difficult to be detected by satellite instruments. These clouds can tremendously impact the remote sensing of aerosols, surface temperature, and atmospheric composition gases. They are also very
important for climate modeling. In this presentation, a novel method for detecting cloud particles in the atmosphere with measuring the polarized sunlight from the Earth-atmosphere system (Sun et al., 2014) is reviewed. Preliminary modeling results suggestthat this method can be used to detect super-thin cirrus clouds having an optical depth of only about 0.06 and super-thin liquidwater clouds having an optical depth of only about 0.01. Such clouds are too thin to be sensed using any current passive satellite
instruments. This method has potential to become an innovative satellite mission of NASA to advance Earth observation fromspace and improve scientific understanding of all clouds and cloud-aerosol interactions.
Reference
Wenbo Sun, Gorden Videen, and Michael I. Mishchenko: Detecting super-thin clouds with polarized sunlight. Geophy. Res.
Lett. 41, doi: 10.1002/2013GL058840 (2014).

キーワード: Remote Sensing, Super-thin clouds, polarized sunlight, angle of linear polarization of light
Keywords: Remote Sensing, Super-thin clouds, polarized sunlight, angle of linear polarization of light

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