Project title: Cold Front vs Cut-off Low (Southeast Iberian Peninsula) – Gota Fría vs DANA (Sureste de la Península Ibérica)

Team: Thaderinos

IES Thader   Orihuela   Spain   25 Student’s age: 14-15 years old

Has the Cold Front (Gota Fría) of the Mediterranean area been transformed into Cut-off Low (DANA), with increasingly disastrous consequences for humans and their environment, due to the direct action of global warming?

The local problem that we have investigated is the flash floods due to cut-off low (in Spanish: DANA, Depresión Aislada en Niveles Altos).
In 2019, we underwent torrential rains that caused severe flooding and destroyed crops and properties. These torrential rains were due to three factors: the existence of a cut-off low (DANA 2019), the wind and the high temperature of the Mediterranean Sea.
So, we decided to perform a study about the flash floods in Orihuela and the influence that global warming can have on them.

Firstly, we started searching for information to decide if a cold front (Gota Fría) was the same as a cut-off low (DANA). According to the Spanish Meteorology Statal Agency (AEMET), the currently accepted term is DANA, cut-off low in English, because it explains how the phenomenon is formed (a part of the jet polar is isolated).

To continue, we documented the damages that occurred in September 2019 due to a DANA. Therefore, we collected pictures of different points of Orihuela in the 2019 flood and compared them with pictures of the same places nowadays. Besides, we also looked for pictures and videos in social media.

Then, we conducted a search about historical floods in Orihuela. Our main source was the Segura River Hydrographic Confederation. After gathering the information, we organised the floods in chronological order (we made a table arranging the floods per century, decade, year and month). Finally, we analysed the data and drew conclusions.

Afterwards, we found some interesting articles with Jorge Olcina as the main researcher where the influence of global warming in the rainfall regime in our area is explained and how it also affects the jet polar.

To finish, we performed a survey about the perception of extreme weather events, natural disasters and climate change effects in our area.

After deciding that the proper name for the cut-off low phenomenon in Spanish is DANA, we analysed the incidence of flash floods in Orihuela. According to our data, the worst decades were 1940s and 1980s (7 floods each) and the worst years were 1924 and 1986 (3 floods), followed by 1906, 1916 and 1997 (2 floods).

When we focused on the month, the 64.6% of the floods took place in autumn, being October the month with a higher incidence. The more dangerous flood met two requirements: the river Segura overflow and the disastrous floodings of the wadis and ravines.

The risk of flooding was studied using two geographic information systems: SNCZI (Agriculture Ministry) and PATRICOVA (Comunitat Valenciana).
To document the air temperature, its anomalies and the amount/days of rain, we used data of the AEMET and other meteorology pages (WeatherSpark, …). The temperature of the Mediterranean Sea was observed with puertos.es and the amount of earthquakes, with ign.es.

We used EO Browser to download images of Orihuela using different filters in the topics: “floods & droughts”, “Agriculture” and “Wildfires”.

We have two presentations given by experts: “Floods in the Vega Baja del Segura: Prevention and Mitigation” by a technical architect and “Climate change and agriculture in the Vega Baja del Segura” by an agricultural engineer.

Then, we applied all that we have learnt into the interpretation of the survey data.
We also played to the interactive game stopdisastersgame.org to learn which was the most effective way to decrease human and economic losses. Then, we applied it to our own models (we used modelling clay for the river in order to change the shape, with and without meanders, and the width).

Finally, we conclude that the global warming is causing a decrease in the speed of the polar jet, so, the DANAs will be more frequent and the torrential rains heavier.

We have adopted several measures to work on the prevention and mitigation of floods, and to spread the knowledge of our project:
– We have invited other groups of our high school to come to the presentations given by experts.
– We have played to https://www.stopdisastersgame.org/stop_disasters/ (flood) and we have taught other people to play. It is important where and how to build houses/hospitals/schools, protecting the water supplies, building defences around the river, etcetera.
– We have made models simulating the entrance of the Segura River in Orihuela. We tried different situations: low or high flow of the river, good and bad infrastructures, with and without meanders.
– We have made a video using our experiences with the models.
– We have created a web page with all the information of the project.
– We have published 4 articles in AulaCheck (a project to create a scientific journal among 30 Spanish Education Centres) explaining different parts of our project. The translated titles could be:
“Is it the same a Cold Front (Gota Fría) than a Cut-off Low (DANA)?”
https://aulacheck.ibercivis.es/2023/02/27/es-lo-mismo-una-gota-fria-que-una-dana/
“How can the global warming affect us?”
https://aulacheck.ibercivis.es/2023/02/28/como-nos-puede-afectar-el-calentamiento-global/
“Floods in the Segura River area: Study, Prevention and Mitigation”
https://aulacheck.ibercivis.es/2023/04/12/inundaciones-en-la-cuenca-del-segura-estudio-prevencion-y-mitigacion/
“Perception of extreme weather events through surveys”
https://aulacheck.ibercivis.es/2023/04/13/percepcion-de-fenomenos-climaticos-extremos-a-traves-de-encuestas/
– We have participated in the “IX Science Exhibition of the Vega Baja” (IX Certamen de Ciencias de la Vega Baja), celebrated 21st and 22nd April 2023 in Orihuela. Approximately 20 institutions presented their projects.
– We have developed two games related to the project: a Kahoot with 4 questions about the project and a boardgame with data about air temperature, sea temperature, weather events and months. The two games were used during the Science Exhibition.
– We are also presenting the project in the “Meeting: The Mediterranean Orchad” (Encuentro: Huerta del Mediterráneo) the 4th May 2023 in Orihuela.

https://sites.google.com/view/gota-fra-vs-dana

Download project poster PDF

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