USAPI USDM: Operational Drought Monitoring in the U.S.-Affiliated Pacific Islands

Richard R Heim,Charles Guard,Mark A Lander,Brandon Bukunt

doi:10.3390/atmos11050495

Abstract

The U.S. Drought Monitor (USDM) has been the de facto operational drought monitoring product for the United States for the last two decades. For most of this time, its coverage included the 50 States and Puerto Rico. In 2019, coverage was expanded to include the U.S.-Affiliated Pacific Islands (USAPI). The geography, geomorphology, and climatology of the USAPI significantly differ from those of the mainland U.S. (CONUS) and they posed a unique challenge for the USDM authors. Following National Oceanic and Atmospheric Administration (NOAA) priorities for development of products in collaboration with users in what is termed “use-inspired science”, NOAA agencies conducted several workshops to identify data and impacts relevant for, and develop drought monitoring criteria appropriate for, the USAPI. Once the criteria were identified and data processing systems were set up, the USAPI were included as part of the operational USDM drought monitoring beginning in March 2019. The drought monitoring criteria consist of weekly and monthly minimum precipitation thresholds for triggering drought, and they follow the USDM “convergence of evidence” methodology for determining the severity level (Dx) of the drought spell.

Highlights

The U.S Drought Monitor (USDM) was created in 1999 [1]
Once the criteria were identified and data processing systems were set up, the U.S.-Affiliated Pacific Islands (USAPI) were included as part of the operational USDM drought monitoring beginning in March 2019
This paper summarizes the results of these user engagements; the unique USAPI hydrological, climatological, and meteorological processes that are relevant to drought; and the system established for analyzing drought in the USAPI as part of the USDM process

Summary

Introduction

The U.S Drought Monitor (USDM) was created in 1999 [1]. As its popularity grew and it became the trigger for many state drought plans and federal drought relief funds [2], the USDM became the de facto operational drought monitoring tool in the United States [3]. To repeat: the “convergence of evidence” approach is dependent on the availability of a large number of indices and indicators that can be converted into a percentile format to capture the temporal, spatial, and sectoral dimensions of drought. The data for these indices and indicators are readily available for the CONUS, being reasonably available for Alaska, Hawaii, and Puerto Rico, but not so readily available for the USAPI and USVI. The limited drought indicators, indices, and data, and the hydrological, climatological, and geographical differences require a slightly different approach for analyzing drought for the USAPI than for the CONUS (the USVI will not be further discussed in this paper). This paper summarizes the results of these user engagements; the unique USAPI hydrological, climatological, and meteorological processes that are relevant to drought; and the system established for analyzing drought in the USAPI as part of the USDM process

The User-Engagement Workshops

The Nature of Drought in the USAPI

Operational Drought Monitoring in the USAPI

16 June 2019

Findings

Summary and Conclusions