1. Introduction

This assessment is the eighth annual climate assessment in an ongoing series produced by the Climate Prediction Center. It is designed to provide a timely summary of the global climate system during 1997, and to document global climate variations, oceanic and atmospheric anomalies in the global Tropics and extratropics, and selected significant regional climate highlights.

Issues related to global and regional climate change, including atmospheric temperatures, ozone, carbon dioxide, and snow cover are addressed in section 2. In section 3a an analysis of the very strong El Niño/Southern Oscillation (ENSO) episode is presented, along with its effects on the atmospheric circulation throughout the tropical Pacific and over the Southern Hemisphere extratropics. Tropical intraseasonal (MaddenJulian oscillation) activity during the year is addressed in section 3b. Regional climate highlights and summaries of the major monsoon systems are discussed in section 4. Topics include flooding in the Red River basin of the north-central United States, a weakened North Atlantic hurricane season, a summary of the rainy seasons in southern, western and eastern Africa, severe drought throughout Indonesia, temperature and precipitation highlights over South America, major flooding in the Czech Republic and eastern Germany during July, and widespread flooding throughout southern China. In section 5, seasonal maps of temperature anomalies, precipitation percentiles, and 500-hPa heights and anomalies are presented. These maps are included for reference, and to continue the set of maps that have appeared in previous Annual Climate Assessments. Although each section is essentially self-contained, there is liberal cross-referencing between sections to aide navigation through the document.

A variety of data sources were used in the compilation of this assessment, including 1) gridded analyses from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/ NCAR) Climate Data Assimilation System/Reanalysis Project (Kalnay et al. 1996), 2) surface data obtained from the operational Global Telecommunications System (GTS), 3) satellites, 4) radiosondes, and 5) ship reports. Selected analyses were also obtained from international climate data centers. It should be noted that due to the variety of different data sources used in the assessment, it is not possible to maintain a consistent base period among all fields when computing anomalies.

Back to Table of Contents