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Uchino, O.

Publications and source records attributed to Uchino, O..

7 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Total Volcanic Stratospheric Aerosol Optical Depths and Implications for Global Climate Change

Understanding the cooling effect of recent volcanoes is of particular interest in the context of the post-2000 slowing of the rate of global warming. Satellite observations of aerosol optical depth above 15 km have demonstrated that small-magnitude volcanic eruptions substantially perturb incoming solar radiation. Here we use lidar, Aerosol Robotic Network, and balloon-borne observations to provide evidence that currently available satellite databases neglect substantial amounts of volcanic aerosol between the tropopause and 15 km at middle to high latitudes and therefore underestimate total radiative forcing resulting from the recent eruptions. Incorporating these estimates into a simple climate model, we determine the global volcanic aerosol forcing since 2000 to be 0.19 +/- 0.09W/sq m. This translates into an estimated global cooling of 0.05 to 0.12 C. We conclude that recent volcanic events are responsible for more post-2000 cooling than is implied by satellite databases that neglect volcanic aerosol effects below 15 km.

aerosols↗
NASA NTRS1994

Multi-wavelength profiles of aerosol backscatter over Lauder, New Zealand, 24 November 1992

Simultaneous profiles of aerosol backscatter ratio were measured over Lauder, New Zealand (45 deg S, 170 deg E) on the night of November 24, 1992. Instrumentation comprised two complementary lidar systems and a backscattersonde, to give measurements at wavelengths 351, 490, 532, and 940 nm. The data from the lidars and the backscattersonde were self-consistent, enabling the wavelength dependence of aerosol backscatter to be determined as a function of altitude. This wavelength-dependence is a useful parameter in radiative transfer calculations. In the stratosphere, the average wavelength exponent between 351 and 940 nm was -1.23 +/- 0.1, which was in good agreement with values derived from measured physical properties of aerosols.

Mckenzie, R. L.↗
NASA NTRS1992

Alexandrite lidar for the atmospheric water vapor detection and development of powerful tunable sources in IR

New tunable solid-state lasers, such as alexandrite and Ti-sapphire lasers, provide a powerful technique to detect various molecules in the atmosphere whose absorption bands are in the infrared region. The differential absorption lidar (DIAL) system to measure the tropospheric water vapor has been investigated by many authors, in an early stage, by dye and ruby lasers. Using the alpha band of water vapor, the longest detection range can be obtained with high accuracy, and the alexandrite laser is the most suitable laser for this purpose. In this paper, we describe the detection of water vapor in the atmosphere by an alexandrite lidar, and the development of powerful tunable sources based on Raman lasers in the infrared region.

Uchiumi, M.↗
NASA NTRS1986

Temperature retrievals by Rayleigh backscatter lidar signals

Differences between retrieved temperatures from lidar and atmospheric model temperatures are calculated for four problems: (1) the effect of a transient thin aerosol layer at any altitude on temperature retrieved by a single-wavelength lidar; (2) the effect of residual aerosols on temperature retrieved by a two-wavelength lidar; (3) the errors due to splicing two backscatter signals which are obtained separately; and (4) the effect of multiple scattering. The results show that temperatures can be retrieved for + or - 3 K if Rayleigh backscatter can be measured for + or - 1.5 percent. The LITE lidar in a 240 km orbit aboard the Shuttle should be able to make a + or -3 K measurements from 10-40 km with vertical resolutions of 1 km and horizontal resolutions of 300 km.

Uchino, O.↗
NASA NTRS1985

Exicimer lidar measurements of ozone

The observation of the atmospheric ozone profile in an altitude range of 3 to 28 km by means of differential absorption lidar in combination with an XeCl laser (308 nm) and SRS pumped by a KrF laser (249 nm) is discussed.

Shibata, T.↗
NASA NTRS1985

UV lidar measurements of the stratospheric aerosol layer and comparison with other optical data

After the violent volcanic eruptions of El Chichon in Mexico (17.33 deg. N, 93.20 deg. W) in late March and early April 1982, enhanced stratospheric aerosols have been monitored by ruby (lasing wavelength lambda=694.3 nm) or Nd:YAG lidars (lambda=1064 or 532 nm). By these lidars, visible or near-infrared optical informations of stratospheric aerosols and their space-time variations can be obtained. It is usually difficult to measure the background level of stratospheric aerosols by an ultraviolet (UV) lidar, since Rayleigh scattering prevails over Mie scattering in the stratosphere. However, after the large volcanic eruptions, UV lidar measurements of stratospheric aerosols are possible. In order to obtain UV optical properties of stratospheric aerosols, measurements have been made at Fukuoka (33.65 deg. N, 130.35 deg. E) by a p-terphenyl dye laser at a wavelength of 340.5 nm. Observational results during October 1982, through May 1983, are shown and are compared with the results obtained by a ruby lidar at Tsukuba (36.05 deg. N, 140.13 deg. E).

Uchino, O.↗