Past IEM Features tagged: arridity

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30, 60, and 90 Day Arridity

19 Jul 2017 05:32 AM
Some of the driest conditions in the state currently can be found over southeastern Iowa. The featured chart looks at the arridity index calculated over 30, 60, and 90 trailing day periods for this year for an areal averaged value representing southeastern Iowa climate district. This index combines temperature and precipitation departures to access water stress. Since early June, the chart shows the increasing stress for this area. There are more chances of rain in the forecast, but the best chances are over northern Iowa.

Voting:
Good: 13
Bad: 0

Tags:   arridity  

Summer Arridity Index

02 Sep 2016 05:18 AM
Arridity Index is a combined measure of temperature and precipitation departures. In this context, the normalized temperature departure is subtracted by normalized precipitation departure. The featured map displays this metric computed over the entire summer by climate district. Positive values indicate areas of increased water stress. For the corn belt, a clear gradient is shown with the far eastern areas under the highest water stress with much of the western portion showing much less stress.

Voting:
Good: 10
Bad: 2

Tags:   arridity  

Comparing Arridities

10 Aug 2016 05:29 AM
Continuing with the recent theme of featuring IEM Arridity plots, today's featured chart compares fourteen trailing day arridities for statewide averaged temperature and precipitation during the 1 May to 8 August period. This year is shown, along with last year and 2012 (drought year). The plot also dynamically includes the closest match to this year's data based on least RMSE , which is 1978. This year has seen much more stress than last year, but pales in comparison to 2012. You can generate this plot for other locations and periods of your choice.

Voting:
Good: 8
Bad: 1
Abstain: 1

Tags:   arridity  

Three Arridities

08 Aug 2016 05:44 AM
The featured chart presents an arridity index evaluated over three different trailing number of days for Ames. The heat and water stress of the first half of the growing season has given way to timely rains and limited periods of very hot weather. This index is computed by taking the standardized departure of average temperature and subtracting the standardized departure of precipitation. You can generate this plot on this website for other locations and for a trailing number of days of your choice.

Voting:
Good: 10
Bad: 0
Abstain: 1

Tags:   arridity  

Spring Arridity

14 Jun 2016 05:34 AM
Continuing on yesterday's featured chart showing a time series of Arridity Index, today's featured map displays the climate district values for the spring months of March, April and May. For Iowa, the eastern two thirds of the state are analyzed at values above zero indicating more water stress than average. You can now generate these maps on this website for a season or month of your choice.

Voting:
Good: 10
Bad: 1

Tags:   arridity  

Arridity Index

13 Jun 2016 05:34 AM
The featured chart displays a time series of an Arridity Index computed for the central Iowa Climate District. There are a number of ways this index can be computed. For the purposes of this plot, it presents the standardized departure of average daily high temperature subtracted by the standardized departure of total precipitation over the past 31 days. The standardization is simply normalizing the departure by the standard deviation of departures for each of the same periods for the period of record years. The index is an attempt to express the additive effects of having anomalously hot and dry weather at the same time. Having either cool and/or wet weather decreases the index value. Rewording, wet weather can help mitigate warm weather. Anyway, no index is perfect and for central Iowa, this index shows the recent increase in June with the arrival of hot and mostly dry weather. Rain has been visiting the state recently, but just not widespread.

Voting:
Good: 7
Bad: 2
Abstain: 2

Tags:   arridity