Monthly review July 2022

Exceptional drought situation in Meißen-Coswig-Radebeul

The second summer month of July presented itself in our region with a mean temperature of 19.9 °C as 1.9 degrees too warm compared to the climate reference period 1961-1990. ln July, the air temperature in Dresden has already risen on average by 2.4 K in the period 1961-2022.
The sun shone for a total of 270 hours. This corresponds to an increase of 65 hours. July 2022 thus reached 10th place in the ranking of all July months since 1961. In July, the sunshine duration in Dresden increased by an average of 46 hours in the period 1961-2022.
After the already extraordinarily dry first half of 2022, the second summer month of July now
brought an even more striking precipitation deficit compared to the reference value 1961-1990. The sum of all individual precipitation measurements in Coswig in July was only 12.8 mm. The monthly total thus corresponded to only 21 % of the reference value for this month. The annual precipitation balance for 2022 so far now totals a clear minus of 135.5 mm. The drought situation in the soil thus reached a state comparable to the extreme drought year 2018. Accordingly, depending on the location, the plants were now exposed to extreme drought and at times also heat stress.
Currently, the drought monitor of the Halle-Leipzig Environmental Research Centre shows that the persistent exceptional drought of the soil down to a depth of 1.8 m has fully re-established itself in our region. The plants are generally no longer able to draw water from the soil (wilting point). Gardeners in Coswig and the surrounding area are now trying to save their perennials, shrubs and young trees from certain withering by watering abundantly.

Weather conditions:
Justified hopes for abundant rainfall in our region were dashed again and again. Not only high-
pressure areas were responsible for this, but also the weakening and dissolution of the approaching precipitation cells on the eastern flank of a westerly flow (due to divergence in higher air layers / Fig. 1) ensured that the already very critical situation in terms of drought now worsened considerably in July. The fires in Saxony on the border with the Czech Republic are still not under control. Stronger rainfall, which would have been useful to contain the fires, has unfortunately failed to materialise, especially in these regions of Saxony. On the Czech side, the situation has not improved yet either.

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Fig.1: Altitude weather map for 500 hPa from 31 July 2022: The map shows a pronounced area of
divergence over eastern Germany. (Image source: Berlin weather map / FU Berlin).

Autor: Wilfried Küchler