Introduction

Abstract

Chapter 1 deals with general problems and methodology: Scope of the study, Basic concepts, Classification criteria: Energy flow, Water stress, Dry seasons and drought, Cold stress and its relationship to latitude and altitude, Frost hazard occurrence, Rainfall distribution and amount, Potential evapotranspiration, P/PET ratios, Temperature and frost sensitivity/tolerance, Relationship between annual temperature and ETo, Ratios between P and ETo as aridity indices, Effect of wind on PET or ETo, Other significant climatic parameters: Vapour pressure, Relative humidity, Saturation deficit, Soil distribution, Impact of agro-hydraulic works, Land-use patterns and agricultural production systems, Flora, Vegetation, Fauna, Wildlife and livestock populations, Human and animal diseases as related to climate, Human comfort.

The methodology is based on a series of criteria at distinct levels of classification:

• Seasonality of rainfall resulting in Mediterranean (winter precipitation, summer drought), Tropical (summer monomodal precipitation, winter drought) and Equatorial (bimodal, spring and fall precipitation, winter and summer drought) families of bioclimates, based on the annual patterns of rain and temperature, as expressed in the climatic diagrams of Bagnouls and Gaussen, popularized by Walter and Lieth in their Klimadiagramm Weltatlas.

• Amount of precipitation and P/PET ratios within each family (hyper-humid, humid, sub-humid, semi-arid, arid to hyper-arid), based on decreasing P/ETo ratios.

• Mean minimum daily temperature of the coldest month as an index of winter cold stress in each family, and its relationship to elevation (lowlands, midlands, highlands and Afro-alpine zones).

A large table (17 pp.) shows the annual values for ten key climatic parameters for the 962 weather stations of the database.