Preface

This book describes aspects of rainfall including the extremes, distribution and properties. The introductory chapter in the first section focusses on drought and flooding rains over Australia, placing extreme rainfall events from recent decades into a historical context. Although recent droughts and floods may often be perceived as unprecedented, when the extended instrumental records are considered, and also proxy reconstructions extend back over hundreds of years, this shows these are recurrent events in the natural climate cycles.

The three chapters in the second section focus on distribution and impacts of rainfall in different parts of the world. The first chapter presents a statistical analysis of rainfall patterns for Jeddah City in Saudi Arabia and considers future impacts. Jeddah has been hit by many rainstorm events during the past decade, which have increased dramatically since 2009, representing changing rainstorm patterns. The study indicated that Jeddah is characterized by two patterns of rainfall: one for rainfall values below 50 mm and the other for values above 50 mm. The second chapter in this section examines rainfall in the context of impacts, vulnerability and climate change in eastern Africa, estimating the causes, vulnerability, impact and adaptation strategies associated with climate change.

The third chapter in Section 2 focusses on a demonstration project initiated by the World Meteorological Organization using space-based weather and climate extremes monitoring. This was established to run for two years (2018-2019) focussing on weather and climate extremes, particularly drought and heavy precipitation over South-East Asia and the Pacific. Case studies presented illustrate drought monitoring in Australia in 2007 and 2018, and also heavy precipitation in Australia in 2010, and Thailand and Malaysia in 2014, which caused widespread flooding.

The third section comprises two chapters that focus on physical and chemical properties of rainfall. One chapter examines the role of aerosols that act as cloud condensation and ice nuclei. These phenomena play critical roles in cloud thermodynamics, and cloud and precipitation microphysics, known as the aerosol indirect effect. In the study presented, aerosol-cloud-precipitation interactions in the Central Himalayas were examined using aerosol observations to specify cloud condensation activation properties for simulations of a pre-monsoon convective storm.

In the final chapter, the relationships between pollutant scavenging effect and the size of raindrops was investigated. Raindrops were collected in Fukuoka City, Japan, and segregated as a function of their size using a specifically designed raindrop collector. The chemical nature of individual size-resolved raindrops was determined. It was found that the elements S, Ca, Si, and Al had relatively high concentrations in raindrops, especially small raindrops. Most of the elements

**II**

**Chapter 6 95**

The Chemical Nature of Individual Size-Resolved Raindrops and Their Residual Particles Collected During High Atmospheric Loading for PM2.5

*by Chang-Jin Ma and Gong-Unn Kang*

measured showed a continuous decrease in concentration with increasing raindrop diameter, and it was concluded that rainfall plays a valuable role in scavenging natural as well as artificial particles from the atmosphere.

> **John Abbot** Institute of Public Affairs, Melbourne, Victoria, Australia

> > University of Tasmania, Tasmania, Australia

> > > **1**

Section 1

Introduction

Climate Modelling Laboratory, Noosa, Queensland, Australia

Section 1 Introduction

**3**

**Figure 1.**

*Map of Australia showing states and locations referred to in this chapter.*

**Chapter 1**

*John Abbot*

**1. Introduction**

this chapter.

Introductory Chapter:

Flooding Rain

Australia—A Land of Drought and

Instrumental records of Australia's rainfall are maintained by the Australian Bureau of Meteorology (BOM) and extend back over 150 years in some locations. Annual contour maps of the continent extending back to 1900 illustrate how annual rainfall has varied across the continent [1]. The continent has a long history of droughts and floods [2], extending into recent years [3, 4]. **Figure 1** shows a map of Australia with the individual states and various locations referred to in
