Tropical cyclones in the North American Regional Reanalysis: The impact of satellite‐derived precipitation over ocean

Abstract

Continued advancement in the realm of tropical cyclone (TC) forecasting requires a more accurate depiction of these storms at model initialization. This study examines the impact of precipitation assimilation on the representation of TCs in the North American Regional Reanalysis before and after the 2004 introduction of precipitation assimilation over ocean in the vicinity of TCs. The probability distribution function of rainfall rates indicates that light (heavy) precipitation was overforecast (underforecast) in the early time period. Since the precipitation assimilation is applied through an adjustment to the latent heating distribution, the data assimilation system in the later time period initializes a low‐level moisture and heating profile that is more conducive to the initiation of deep convection and the generation of precipitation. Consequently, the deep convection and enhanced latent heat release lead to a more robust warm‐core temperature perturbation and a better developed secondary circulation, which supplies the TC with larger quantities of moisture from the large‐scale environment. Furthermore, the evolution of TC size, which was objectively estimated though the radius of outermost closed isobar, is significantly more skillful (p < 0.05) in post‐2003 storms. Based on this study, precipitation assimilation leads to a better analysis of temperature, winds, and moisture in the vicinity of TCs, resulting in improved representations of the water budget and storm life cycle. Therefore, we conclude that efforts toward the development of precipitation assimilation techniques from radar and satellite data sets will be valuable toward the construction of improved TC forecasting tools with more authentic TC representation.

Spatial characteristics of storm‐total rainfall swaths associated with tropical cyclones over the Eastern United States

“…Also, this study investigated the associations between several TC attributes and change in rainfall width. Although data span a shorter period and display some inconsistencies in representing TCs over the long‐term (Zick and Matyas, ), the North American Regional Reanalysis dataset has a similar spatial resolution to the GPM and TRMM datasets and could be employed to investigate synoptic‐scale conditions (e.g. total precipitable water, vertical wind shear, temperature and moisture gradients associated with frontal boundaries) that may contribute to rain field expansion after landfall.…”

Measuring Radial and Tangential Changes in Tropical Cyclone Rain Fields Using Metrics of Dispersion and Closure

“…Due to a relatively high spatial (32 km × 32 km) and temporal (3 h) resolution, we extract data for specific humidity and vertical wind shear from the North American Regional Reanalysis (NARR) [46]. Zick and Matyas [47] demonstrated that Jeanne and Humberto were well represented in this dataset. To summarize moisture and shear, we employ the same calculations as in the Statistical Hurricane Intensity Prediction Scheme [48], which produce areal averages by considering data 200-800 km from the storm center.…”

High‐Resolution Regional Reanalysis in China: Evaluation of 1 Year Period Experiments

“…Several regional reanalysis data sets have been produced over North America, Europe, and the Arctic during last 10 years: North American Regional Reanalysis (NARR) (Mesinger et al, 2006), the High-resolution Regional Reanalysis for the Europe (Bollmeyer, Keller, et al, 2015;Dahlgren et al, 2016;Renshaw et al, 2013), and the regional Arctic system reanalysis (Bromwich et al, 2016). Using these regional reanalyses, researchers have carried out studies on tropical cyclones (Zick et al, 2015a(Zick et al, , 2015b, droughts (Sheffield, Wood, & Roderick, 2012), thunderstorms (Gensini et al, 2013), and hydrologic processes in mountainous terrain (Trubilowicz et al, 2016).…”