Masatomo Fujiwara

Abstract. The climate research community uses atmospheric reanalysis data sets to understand a wide range of processes and variability in the atmosphere, yet different reanalyses may give very different results for the same diagnostics. The Stratosphere–troposphere Processes And their Role in Climate (SPARC) Reanalysis Intercomparison Project (S-RIP) is a coordinated activity to compare reanalysis data sets using a variety of key diagnostics. The objectives of this project are to identify differ

In this paper, we describe the construction of the Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database, which includes vertically resolved ozone and water vapor data from a subset of the limb profiling satellite instruments operating since the 1980s. The primary SWOOSH products are zonal-mean monthly-mean time series of water vapor and ozone mixing ratio on pressure levels (12 levels per decade from 316 to 1 hPa). The SWOOSH pressure level products are provided on several indep

Abstract. Two of the most basic parameters generated from a reanalysis are temperature and winds. Temperatures in the reanalyses are derived from conventional (surface and balloon), aircraft, and satellite observations. Winds are observed by conventional systems, cloud tracked, and derived from height fields, which are in turn derived from the vertical temperature structure. In this paper we evaluate as part of the SPARC Reanalysis Intercomparison Project (S-RIP) the temperature and wind structu

Reanalysis data sets are widely used to understand atmospheric processes and past variability, and are often used to stand in as "observations" for comparisons with climate model output. Because of the central role of water vapor (WV) and ozone (O₃) in climate change, it is important to understand how accurately and consistently these species are represented in existing global reanalyses. In this paper, we present the results of WV and O₃ intercomparisons that have been per

A polarization lidar was continuously operated aboard the research vessel Mirai in the tropical western Pacific over three northern winters: at 2.0°N, 138.0°E during November and December 2001; at 2.0°N, 138.5°E during November and December 2002; and at 7.5°N, 134.0°E during December 2004 and January 2005. Intensive radiosonde soundings were made from the vessel at 3‐h intervals during all three campaigns. The mechanisms that underlie the observed variations in cirrus in the tropical tropopause

Pronounced enhancements of total and tropospheric ozone were observed with the Brewer spectrophotometer and ozonesondes at Watukosek (7.5°S, 112.6°E), Indonesia in 1994 and in 1997 when extensive forest fires were reported in Indonesia. The integrated tropospheric ozone increased from 20 DU to 40 DU in October 1994 and to 55 DU in October 1997. On October 13, 1994, most ozone mixing ratios were more than 50 ppbv throughout the troposphere and exceeded 80 ppbv at some altitudes. On October 22, 19

An intensive observation with ozonesondes and rawinsondes was conducted in Indonesia in May and June 1995 to investigate a phenomenon of ozone enhancement in the tropical upper troposphere. We obtained the characteristics of an enhancement that continued for about 20 days, concurring with a zonal wind oscillation associated with the equatorial Kelvin wave around the tropopause and the Madden‐Julian oscillation (MJO) in the troposphere. The isoline of ozone mixing ratio of 40 nmol/mol moved by 5.

Abstract. We validate the Ozone Monitoring Instrument (OMI) Ozone Profile (PROFOZ) product from October 2004 through December 2014 retrieved by the Smithsonian Astrophysical Observatory (SAO) algorithm against ozonesonde observations. We also evaluate the effects of OMI row anomaly (RA) on the retrieval by dividing the dataset into before and after the occurrence of serious OMI RA, i.e., pre-RA (2004–2008) and post-RA (2009–2014). The retrieval shows good agreement with ozonesondes in the tropic

We investigated water vapor variations in the tropical lower stratosphere on seasonal, quasi‐biennial oscillation (QBO), and decadal time scales using balloon‐borne cryogenic frost point hygrometer data taken between 1993 and 2009 during various campaigns including the Central Equatorial Pacific Experiment (March 1993), campaigns once or twice annually during the Soundings of Ozone and Water in the Equatorial Region (SOWER) project in the eastern Pacific (1998–2003) and in the western Pacific an

The ''Snow White'' hygrometer is a low-cost, chilled-mirror hygrometer for radiosonde applications provided by a Swiss company, Meteolabor AG. A total of 54 Snow White soundings were conducted at five tropical stations in different seasons in 2000-01. All soundings were made with Vaisala RS80 radiosondes equipped either with the A-Humicap (22 soundings) or H-Humicap (32) relative humidity (RH) sensor. Comparisons of the RH with respect to liquid water between the Snow White and the different RS8

Soundings of frost‐point hygrometers, ozonesondes, and radiosondes at San Cristóbal Island (0.9°S, 89.6°W) in September 1998 provide an observational evidence that equatorial Kelvin waves around the tropopause act as a dehydration pump for the stratosphere. During the downward‐displacement phase of a Kelvin wave, dry and ozone‐rich stratospheric air is transported into the upper troposphere. During the upward‐displacement phase, on the other hand, higher specific‐humidity air moves up in the tro

The Equatorial Atmosphere Radar (EAR) installed in Sumatra Island, Indonesia, observed significant enhancement of turbulence in the tropopause region, 15–17 km, intermittently for ∼5 days in November 2001. The turbulence intensity was estimated with the spectral width of the radar echo power spectrum, and the turbulence during the period was a factor of up to ∼5 larger in kinetic energy than that in other periods. Further analyses confirm that the enhanced turbulence was convectively generated i

Regular ozonesonde observation and total ozone observation with the Brewer spectrophotometer have been conducted at Watukosek (7.5°S, 112.6°E), Indonesia, since 1993. Three seasons are recognized for the vertical distribution of tropospheric ozone. (1) During the local wet season, between December and March, the ozone mixing ratio is nearly constant at 25 ppbv throughout the troposphere. (2) During the transition season from wet to dry, between April and July, the mixing ratio is often enhanced

Abstract. We observed ozone (O3) in the vertical region between 250 and 0.0005 hPa (~ 12–96 km) using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the Japanese Experiment Module (JEM) of the International Space Station (ISS) between 12 October 2009 and 21 April 2010. The new 4 K superconducting heterodyne receiver technology of SMILES allowed us to obtain a one order of magnitude better signal-to-noise ratio for the O3 line observation compared to past spaceborne micr

Abstract. The global temperature responses to the eruptions of Mount Agung in 1963, El Chichón in 1982, and Mount Pinatubo in 1991 are investigated using nine currently available reanalysis data sets (JRA-55, MERRA, ERA-Interim, NCEP-CFSR, JRA-25, ERA-40, NCEP-1, NCEP-2, and 20CR). Multiple linear regression is applied to the zonal and monthly mean time series of temperature for two periods, 1979–2009 (for eight reanalysis data sets) and 1958–2001 (for four reanalysis data sets), by considering