Analysis and Forecast Using Dropsonde Data from the Inner-Core Region of Tropical Cyclone Lan (2017) Obtained during the First Aircraft Missions of T-PARCII

Abstract

The inner core of Tropical Cyclone Lan was observed on 21− 22 October 2017 by GPS dropsondes during the first aircraft missions of the Tropical Cyclones-Pacific Asian Research Campaign for the Improvement of Intensity Estimations/Forecasts (T-PARCII). To evaluate the impact of dropsondes on forecast skill, 12 36-h forecasts were conducted using a Japan Meteorological Agency non-hydrostatic model (JMA-NHM) with a JMA-NHM-based mesoscale four-dimensional data assimilation (DA) system. Track forecast skill improved over all forecast times with the assimilation of the dropsonde data. The improvement rate was 8−16% for 27−36-h forecasts. Minimum sea level pressure (Pmin) forecasts were generally degenerated (improved) for relatively short-term (long-term) forecasts by adding the dropsonde data, and maximum wind speed (Vmax) forecasts were degenerated. Some of the changes in the track and Vmax forecasts were statistically significant at the 95% confidence level. It is notable that the dropsonde-derived estimate of Pmin was closer to the realtime analysis by the Regional Specialized Meteorological Center (RSMC) Tokyo than the RSMC Tokyo best track analysis. The degeneration in intensity forecast skill due to uncertainties in the best track data is discussed.

Estimation of the Tangential Winds and Asymmetric Structures in Typhoon Inner Core Region Using Himawari‐8

“…The inner core of Typhoon Lan was observed from 21 to 22 October by GPS dropsondes during the first aircraft missions of the Tropical Cyclones‐Pacific Asian Research Campaign for the Improvement of Intensity Estimations/Forecasts (Ito et al, 2018). For verification, we used a dropsonde profile obtained at r ~20 km at around 6:50 UTC, 21 October.…”

The SOLA Award in 2018

“…The Editorial Committee of Scientific Online Letters on the Atmosphere (SOLA) gives The SOLA Award to outstanding paper(s) published each year. I am pleased to announce that The SOLA Award in 2018 is going to be presented to the paper by Dr. Kosuke Ito et al, entitled with "Analysis and forecast using dropsonde data from the inner-core region of Tropical Cyclone Lan (2017) obtained during the first aircraft missions of T-PARCII" (Ito et al 2018).…”

Inner‐Core Wind Field in a Concentric Eyewall Replacement of Typhoon Trami (2018): A Quantitative Analysis Based on the Himawari‐8 Satellite

“…After September 25, 2018, the moving direction of the storm turned northward with a slow‐moving speed of about 2–3 m s −1 , and the storm intensity gradually weakened. The special aircraft campaign of the Tropical cyclones‐Pacific Asian Research Campaign for Improvement of Intensity estimations/forecasts (T‐PARCII) project (Ito et al., 2018; Yamada et al., 2018) conducted dropsonde observations by penetrating into the eye at multiple times during the mature and decaying stages (i.e., September 25–28, 2018).…”