Real-Time Adaptive Observation Guidance Using Singular Vectors for Typhoon Jangmi (200815) in T-PARC 2008

Abstract

In this study, structures of real-time adaptive observation guidance provided by Yonsei University (YSU) in South Korea during The Observing System Research and Predictability Experiment (THORPEX)-Pacific Asian Regional Campaign (T-PARC) are presented and compared with those of no-lead-time adaptive observation guidance recalculated as well as other adaptive observation guidance for a tropical cyclone (Jangmi 200815). During the T-PARC period, real-time dry total energy (TE) singular vectors (SVs) based on the fifthgeneration Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) and the corresponding tangent linear and adjoint models with a Lanczos algorithm are provided by YSU to help determine sensitive regions for targeted observations. While YSU provided the real-time TESV guidance based on a mesoscale model, other institutes provided real-time TESV guidance based on global models. The overall features of the real-time MM5 TESVs were similar to those generated from global models, showing influences from tropical cyclones, midlatitude troughs, and subtropical ridges. TESV structures are very sensitive to verification region and forecast lead time. If a more accurate basic-state trajectory with no lead time is used, more accurate TESVs, which yield more accurate determinations of sensitive regions for targeted observations, may be calculated. The results of this study may imply that reducing forecast lead time is an important component to obtaining better sensitivity guidance for real-time targeted observation operations.

Statistical adjoint sensitivity distributions of meteorological forecast errors of Asian dust transport events in Korea

“…(1 ) (Langland et al, 2002;Kim and Jung, 2006;Kim et al, 2011 The sensitivity frequency is calculated as follows:…”

“…Until recently, many studies used adaptive observation strategies to identify sensitive regions for adaptively observing extratropical or tropical cyclones (e.g. Reynolds, 2005, 2006;Kim and Jung, 2006;Majumdar et al, 2006;Wu et al, 2007;Kim et al, 2008aKim et al, , 2011Kim and Jung, 2009a, b;Jung et al, 2010;Park et al, 2013).…”

Statistical distributions of singular vectors for tropical cyclones affecting Korea over a 10-year period

“…As in Kim and Jung (2009a, b) and Kim et al (2011a), this study used the fifth-generation Pennsylvania State University/NCAR Mesoscale Model (MM5), together with the MM5 adjoint modeling system (Zou et al 1997) and a Lanczos algorithm, to calculate TESVs. The model domain included 70 9 60 horizontal grids (centered at 36°N, 125°E), with a 100-km horizontal resolution and 14 evenly spaced sigma levels in the vertical, from the surface to 50 hPa.…”

“…Adaptive (or targeted) observations have been applied to TCs to increase the accuracy of TC forecasts by decreasing the initial condition uncertainties Reynolds 2005, 2006;Jung 2006, 2009a, b;Kim et al 2011a;Jung et al 2012;Majumdar et al 2006;Wu et al 2007Wu et al , 2009aLang et al 2012). The observational regions detected by adaptive observation strategies are called sensitive regions because the observations in those regions may have a large influence on enhancing weather forecasts (Kim et al 2004a).…”

“…where i and j denote grid points in the x and y directions, k 2 1 and k 2 n are singular values for the first and the nth TESVs, respectively, and S n ij denotes the nth vertically integrated TESV energy field as in Kim and Jung (2009b) and Kim et al (2011a).…”