The University of Tokyo · Earth and Planetary Sciences
Professor M. Koike's research lab specializes in atmospheric chemistry and remote sensing, focusing on trace gas and aerosol measurements in the stratosphere and troposphere. The lab conducts long-term ground-based observations using Fourier transform infrared (FTIR) spectroscopy to study atmospheric constituents such as HNO₃, CO, and cloud condensation nuclei, particularly in polar and mid-latitude regions. Key research directions include the impact of volcanic eruptions on stratospheric chemistry, the role of aerosols in ozone depletion, and the seasonal and regional variability of tropospheric pollutants. The lab also integrates in situ measurements with global chemistry transport modeling to better understand atmospheric processes and pollution sources.
Figures are computed from collected data and may differ slightly.
Ground based infrared observations of HNO 3 column amount at Lauder, New Zealand (45°S, 170°E), show significant increases in HNO 3 following the arrival of Pinatubo volcanic aerosols. The increase first became apparent in September 1991 when the HNO 3 amount was higher than that expected from the regular seasonal variation by 2.3 × 10 15 cm −2 , which corresponds to 16% of the unperturbed value. Between September 1991 and May 1993, the observed HNO 3 amounts were systematically higher, typicall
Abstract Two years of continuous in situ measurements of Arctic low‐level clouds have been made at the Mount Zeppelin Observatory (78°56′N, 11°53′E), in Ny‐Ålesund, Spitsbergen. The monthly median value of the cloud particle number concentration ( N c ) showed a clear seasonal variation: Its maximum appeared in May–July (65 ± 8 cm −3 ), and it remained low between October and March (8 ± 7 cm −3 ). At temperatures warmer than 0 °C, a clear correlation was found between the hourly N c values and t
Tropospheric carbon monoxide (CO) was measured throughout 2001 using ground‐based Fourier transform IR (FTIR) spectrometers at Moshiri (44.4°N) and Rikubetsu (43.5°N) observatories in northern Japan, which are separated by 150 km. Seasonal and day‐to‐day variations of CO are studied using these data, and contributions from various CO sources are evaluated using three‐dimensional global chemistry transport model (GEOS‐CHEM) calculations. Seasonal maximum and minimum FTIR‐derived tropospheric CO a
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