Impact of Wind Profile Retrievals on the Analysis of Tropical Cyclones in the JRA-25 Reanalysis

Hatsushika, Hiroaki; Tsutsui, Junichi; Fiorino, Michael; Onogi, Kazutoshi

doi:10.2151/jmsj.84.891

Cited by 54 publications

(74 citation statements)

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“…As another method, we should utilize reanalysis products. Hatsushika et al (2006) investigated the TC detection rate in the Japanese 25-years Reanalysis (JRA-25, Onogi et al 2007), and obtained a detection rate of 90%. Hsu et al (2008) extracted TC wind fields from European Centre for Medium-Range Weather Forecasts (ECMWF) 40-years reanalysis project (ERA-40, Uppala et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Mean Features of Tropical Cyclone Precipitation from TRMM/3B42

Kamahori¹

2012

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The mean features of precipitation distribution associated with tropical cyclones are evaluated as anomalies from environmental precipitation fields, in six tropical cyclone active basins, using satellite-derived daily precipitation observation. A common feature in all basins is that concentric positive precipitation anomalies extend within a 5-degree radius from the tropical cyclone center with maximum values of 70 to 100 mm day −1 . These distributions are well approximated by a Gaussian curve with an e-folding radius of 2.2 to 2.8 degrees. Positive precipitation anomalies are surrounded by negative anomalies in all basins, indicating suppression of precipitation due to the tropical cyclones themselves at a large distance from the center. The negative anomalies have minimum values of −2 to −3 mm day −1 and are distributed mainly on the equatorial side of the center. Precipitation excess frequency around the tropical cyclones is also evaluated. The western North Pacific has maximum values of excess frequencies in all basins, in which the frequency for 100 mm day −1 is 26 days yr −1 and that for 200 mm day −1 is 1.8 days yr −1 within a 1-degree radius from the center. We assume that tropical cyclones in the western North Pacific have the greatest precipitation intensity.

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Section: Discussionmentioning

confidence: 99%

Mean Features of Tropical Cyclone Precipitation from TRMM/3B42

Kamahori¹

2012

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“…TCR data is effective in reproducing tropical cyclones and surrounding atmospheric conditions (Hatsushika et al 2006). Figure 10 shows examples of sea level pressures analysis around TC with observed TC locations in September 1990 in the JRA-25.…”

Section: Tropical Cyclonesmentioning

confidence: 99%

The JRA-25 Reanalysis

Onogi

Tsutsui

Koide

et al. 2007

Journal of the Meteorological Society of Japan

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A long-term global atmospheric reanalysis, named ''Japanese 25-year Reanalysis (JRA-25)'' was completed using the Japan Meteorological Agency (JMA) numerical assimilation and forecast system. The analysis covers the period from 1979 to 2004. This is the first long-term reanalysis undertaken in Asia. JMA's latest numerical assimilation system, and specially collected observational data, were used to generate a consistent and high-quality reanalysis dataset designed for climate research and operational monitoring and forecasts. One of the many purposes of JRA-25 is to enhance the analysis to a high quality in the Asian region.Six-hourly data assimilation cycles were performed, producing 6-hourly atmospheric analysis and forecast fields of various physical variables. The global model used in JRA-25 has a spectral resolution of T106 (equivalent to a horizontal grid size of around 120 km) and 40 vertical layers with the top level at 0.4 hPa. In addition to conventional surface and upper air observations, atmospheric motion vector (AMV) wind retrieved from geostationary satellites, brightness temperature from TIROS Operational Vertical Sounder (TOVS), precipitable water retrieved from orbital satellite microwave radiometer radiance and other satellite data are assimilated with three-dimensional variational method (3D-Var). JMA produced daily sea surface temperature (SST), sea ice and three-dimensional ozone profiles for JRA-25. A new quality control method for TOVS data was developed and applied in advance.Many advantages have been found in the JRA-25 reanalysis. Predicted 6-hour global total precipitation distribution and amount are well reproduced both in space and time. The performance of the long time series of the global precipitation is the best among the other reanalyses, with few unrealistic variations from degraded satellite data contaminated by volcanic eruptions. Secondly, JRA-25 is the first reanalysis to assimilate wind profiles around tropical cyclones reconstructed from historical best track information; tropical cyclones were analyzed properly in all the global regions. Additionally, low-level cloud along the subtropical western coast of continents is well simulated and snow depth analysis is also of a good quality. The article also covers material which requires attention when using JRA-25.

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“…As a TC bogusing technique, wind profile data (TCR data;Fiorino 2002) are inserted at the cyclone center and at 2° away from the center in the four cardinal directions from 1000 hPa up to 400 hPa level (Hatsushika et al 2006). Vertical profile of each retrieved wind is designed to represent a warm core structure of a TC.…”

Section: Data and Analysis Methodsmentioning

confidence: 99%

“…However, the TCR data were created on the basis of Neumann's best track dataset (Hatsushika et al 2006). Consequently, although a TC in the JMA best track is identified with a series of the TCR data for a certain period during its lifetime, the time when the last TCR data is identified for each TC may correspond neither to the ET time nor to the time when the TC was downgraded to a storm with a maximum wind speed less than 30 knots in the JMA best track data.…”

Section: Data and Analysis Methodsmentioning

confidence: 99%

“…One of the major advantages of the Japanese 25-year Reanalysis (JRA-25; Onogi et al 2007) is representation of TC structures by means of assimilating wind profile data retrieved from TC best track information (Hatsushika et al 2006) that is similar to the TC bogusing used by Heming and Radford (1998). However, impact of removal of the retrieved winds at the ET stage has not been investigated.…”

Section: Introductionmentioning

confidence: 99%

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Impact of Synthetic Wind Retrieval on Tropical Cyclone Structures at the Extratropical Transition Stage in the JRA-25 Reanalysis

Kitabatake¹

2010

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Structures of 266 tropical cyclones (TCs) that completed extratropical transition (ET) in the western North Pacific during 1979−2004 are examined using the JRA-25 dataset, in relation to the removal of TC wind profile retrievals (TCR) from each TC after its recurvature. The TCR is a kind of "TC bogusing" techniques, and it was expected that its removal may lead to an artificial change in the TC structure at the ET stage. Nearly half of the examined TCs have cold-core structures before the removal of the TCR. On average, the structural change associated with ET starts more than one day before the removal of the TCR. Direct impact of the warm-core structure of the TCR is limited within a radius of about 200 km from the TC center. Although discontinuity in the TC structure between the periods with and without TCR may be statistically significant, the differences in the indices are practically negligible.

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Impact of Wind Profile Retrievals on the Analysis of Tropical Cyclones in the JRA-25 Reanalysis

Cited by 54 publications

References 23 publications

Mean Features of Tropical Cyclone Precipitation from TRMM/3B42

Mean Features of Tropical Cyclone Precipitation from TRMM/3B42

The JRA-25 Reanalysis

Impact of Synthetic Wind Retrieval on Tropical Cyclone Structures at the Extratropical Transition Stage in the JRA-25 Reanalysis

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