GB/T 21987-2017Grades of cold wave (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 21987-2008. Compared with GB/T 21987-2008, in addition to editorial changes, the main technical changes as follows.

--- Removed normative references (see Chapter 2 of the 2008 edition);

--- Removed the terms "cold wave process" "average daily temperature" and "average daily temperature drop range"; revised the term "daily minimum temperature" Definition; added the term "within 24 hours of cooling rate" "48 hours of cooling rate" "72 hours of cooling rate" (see Chapter 2, Chapter 3 of the 2008 edition);

--- Modify "Single Station Cold Tide Strength Level" as "Cold Tide Strength Level Division" and delete the original "4.3 Cold Tide", "4.4 Strong Cold Tide" and The "(or average daily temperature)" in "4.5 Extreme cold wave" (see Chapter 3, Chapter 4 of the 2008 edition);

--- Removed the "regional cold tide intensity level" and "national cold tide intensity level" two chapters and all contents (see the 2008 edition of Chapter 5 and Chapter 6).

Introduction

Cold wave is one of the major disastrous weather, it has the characteristics of large temperature range, wide range of impact, serious disaster and so on, not only will cause nationals Economy, especially agriculture and forestry, animal husbandry production, but also on people's lives, health have a serious impact and harm. for To unify and standardize the grading standards that affect cold spell in our country so as to standardize and standardize the forecast, early warning, research and prevention of cold waves In 2008, the preparation of national standards GB/T 21987-2008 "cold level".

For a long time, China's meteorologists have done a great deal of research on the cold wave standards. Due to the vast territory of our country, the natural geography around it Different in the environment, cold air activity varies greatly between the north and south, therefore, the cold surge standards adopted by different places are not uniform. The purpose of this standard revision is to simplify GB/T 21987-2008 content, the cold wave forecast, early warning services more standardized, standardized, scientific and operational.

1 Scope

This standard specifies the cold tide intensity level and its classification.

This standard applies to cold wave monitoring, forecasting, alerting and assessment and scientific research.

2 Terms and definitions

The following terms and definitions apply to this document.

3 Cold intensity level division