Dr. Victor L. Martin
While this column isn’t really long enough for a great deal of information, with the summer the area is having it might be informative to address what the terms “weather” and “climate” really define and what these words mean to us as we swelter through this summer. First let’s start with a few definitions so we are all on the same page and go from there. What isn’t covered today can be finished up next week. Since my background is in agronomy and soils, we’ll approach the topic from that direction.
· Weather – stick your head out the door for a second and you’ll be able to describe the weather. Weather is simply the condition of the atmosphere at or over a given period of time. Typically weather is described in terms of temperature, solar radiation and/or cloudiness, humidity, wind speed and direction, and other terms you commonly hear when you listen or watch a weather forecast. For farmers you can add terms like Growing Degree Days and PET (Potential Evapotranspiration). In agronomic terms, knowing the weather during a growing season can help you understand how a crop may develop or looking back after harvest, examining the weather can help explain what happened or didn’t happen to a crop. The weather forecast may also be used to help make decisions regarding crop management decisions. It can’t tell you what crops are suited to an area but can tell you why they performed the way they did.
· Climate – this term takes in a longer view of atmospheric conditions. Climate won’t tell you what the weather is at any given time but describes the generally prevailing weather conditions of a region (temperature regime, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years, typically decades to hundreds of years). Unlike weather, understanding the climate of an area helps identify the suitability of crops and livestock to a given region. However, climate can’t explain why a crop behaved the way it did for a given year. Instead it describes the “average” of items like moisture and temperature regimes and moisture distribution. Looking at our climate, explains why hard winter wheat is suited to our climate by lowland rice typically of southeast Asia isn’t and vice versa.
One important thing to remember is that weather conditions are like many aspects of our environment since they affect a number of different factors. An example from this spring is the lack of rust diseases in the wheat crop. The dry conditions were unfavorable for disease development so while the wheat suffered from drought conditions, so did diseases.
An example of the complex relationship of climate to our environment is our soils. Climate affects soil development in not one but two ways and is one of the five major soil forming factors. Climate determines the rate of soil formation (increasing as precipitation increases and with warmer temperatures). Climate also affects soil formation since the climate determines what plant and animal life can exist. This explains the grasslands of the Great Plains, the forests east of the Mississippi, and the different soils that developed under each. One last thought before we pick this up next week. You have to examine the climate in total, not just one aspect of it. A quick example is simply comparing the precipitation totals from say Ireland and Southeast Kansas. Take a second and decide which area receives more rainfall on average. The answer is extreme Southeast Kansas. What’s the difference? We’ll cover that next week.