2023-08-04 03:20:00
Sader Planes of the Mexican Air Force carry out flights to stimulate the rains in various regions of Mexico.
Over the state of Sinaloa, where on the ground the Mexican army carries out security work, for the last three years some Mexican Air Force planes have been flying over with other types of “weapons”..
On board they transport containers with a valve that must be opened at the right place and time to hit the target.
His goal has become very necessary: make it rain in regions suffering from increasing water stress.
The strategy has been colloquially called “bombardment” or “cloud seeding”, but technically it is a “rain stimulation”.
According to official figures, has achieved an increase in rainfall of between 35% and 60% in the areas where it has been applied.
And it is carried out in north-central states of the country, such as Sinaloa, where the rains no longer arrive in the same amount as before or appear late in the agricultural season.
Also where cattle pastures have not grown due to lack of water, as well as in the basins that serve as a supply for large cities with water problems such as Monterrey.
“We have been facing a process of desertification in the world, and Mexico is no exception,” engineer Santiago Argüelles Campos, one of the coordinators of the strategy of the Ministry of Agriculture and Rural Development (Sader), explained to BBC Mundo.
“For us, this strategic project is an innovation given the drought conditions that have prevailed since 2019,” he says.
Although the effectiveness numbers reported by Sader are very encouraging, researchers in the field of atmospheric sciences consider that up to now there is no strong evidence that this type of project works at a level that impacts.
But what do cloud flybys do and how are their results measured?
How does it work?
Since the middle of the 20th century, scientists in various parts of the world have been testing methods to modify the weather, mainly in terms of precipitation of rain or snow. The American scientist Vince Schaefer is known for being the creator of the “cloud seeding”.
In Mexico there were similar experiments for decades with results that “were never conclusive”according to researchers Fernando García García and Guillermo Montero Martínez, from the Cloud Physics Group of the Institute of Atmosphere Science and Climate Change.
Conagua Droughts have worsened in the north-central regions of Mexico in recent years.
But since 2019, Sader has been promoting a new rainfall stimulation strategy with an innovative Mexican method, explains Argüelles.
“We do not seek or intend to create cloudiness, but simply work on the paths of cloudiness that occur in normal weather conditions,” he says.
Clouds form when rising air cools to a point where the temperature condenses the water vapor it contains.
“It is very similar to when in the shower the steam condenses on the mirror and drops form. It is the same condensation mechanism in the atmosphere”, explains researcher Katja Friedrich, from the Department of Atmospheric and Oceanic Sciences at the University of Colorado (USA), to BBC Mundo.
To “bomb” the clouds, in Mexico they use the aircraft of the FAM (and other public and private entities that have joined the project), to which sprinklers and pressurization tanks are installed.
“In the polygon that we have defined and under cloudy conditions, a solution of silver iodide in acetone is spread that stimulates the formation of condensation nuclei,” explains Argüelles.
SADER Silver iodide helps clouds precipitate the water they contain.
The presence of such a chemical agent stimulates the fall of rain that it is already in the clouds present in the chosen region and that, due to natural factors, could dissipate and not precipitate. That is why this Mexican method does not seek to create clouds, but to influence those that already exist in the atmosphere.
In 2023 the program has been applied in 10 polygons care in regions that suffer from water stress in the central, northern and western states of the country such as Aguascalientes, Chihuahua, Coahuila, Durango, Sinaloa, Sonora, Tamaulipas and Zacatecas, among others.
How do you measure its effectiveness?
The polygons where rainfall is stimulated can be as large as two million hectares. In those areas, the National Meteorological Service (SMN) has historical rainfall records and calculates how much rain is expected to fall based on statistical models.
After spraying from the flights, there are rain gauges on the ground with which the authorities measure precipitation in addition to the regular average What would the SMN expect for that specific period?
Con 250 flights carried out, the team has recorded that between one and two thirds more rain falls. “That means that the average precipitation in addition to what was expected has been between 35% and 60%. And it is important to say that they have defined three parameters”, Argüelles points out.
These are: the increase in rainfall of between 35% and 60% compared to that expected by the SMN; a 100% efficiency, because every time they have sprinkled, rain has been generated; and one 93% effectivenesswhich indicates the number of polygons that have received rain compared to what was projected.
Sader Officials are analyzing what type of cloudiness they can stimulate with silver iodide.
“In general, we select areas of high water stress, crop planting areas, mainly basic grains, or meadows that have priority for food self-sufficiency goals, and ravines or basins that have significant runoff towards dams that manage water for human consumption. or agricultural irrigation”, explains the official.
The latter has an impact on large cities, such as Monterrey or Mexico Citysince some of the overflights have stimulated rains over basins that supply dams and other water management systems for the demand of those cities.
“Now that we have the El Niño phenomenon, the SMN explained to us that we were going to find more cloudiness in the Pacific, in the center of the country, without this necessarily implying more precipitation. So it is an opportunity to implement this innovation, to take advantage of that cloudiness”, points out Argüelles.
Is it the great solution to droughts?
From Sader they emphasize that this project has benefited areas with high water stress that no longer have the volumes of water necessary for agricultural irrigation, or in those regions where the rains are late and the sowing cycles pass and they no longer have a chance to sow
They have also observed an increase in grassland vegetation, something that benefits the cattle industry. And they have even used the stimulation of rain to mitigate forest fires, such as the one that occurred this year in the Sierra de Arteaga, Coahuila.
Sader The FAM aircraft have sprinklers that allow the “bombardment” of clouds.
However, experts suggest that The results of this type of project must be taken with caution.. There are many variables in the climate that make it impossible to be certain in the studies of the stimulation of rain and it is not only possible to make an arithmetic calculation.
It is difficult to measure whether the amount of rainfall is increased by strategies such as cloud seeding or bombardment, since rainfall tends to vary from year to year in the same region. In addition, between regions of the same country there are different rainfall patterns that do not make them comparable.
“Precipitation is highly variable to see how much the impact really changes from one year to the next”says Friedrich, who has seen results of between 5% and 30%. A significant change, he points out to her, could be more than 20%.
A long-term study, of several years or even decadesis the one that could yield an accurate result on whether a strategy such as cloud stimulation in Mexico is working.
Sader La Sader ensures that the level of silver iodide is not risky for human health or the environment.
Argüelles acknowledges that there have been doubts regarding the country’s strategy, but points out that there is “much confusion” among some of the analysts due to the various methods that exist in the world. “They refer to other types of technologies, some on the creation of clouds, we do not focus on it,” he argues.
“What we have said is that with this technology, for us, we have quantified the resultsthe increases in precipitation and the cost-benefit that is positive”, he adds.
The official also explains that the stimulation of rainfall is not considered by the government as the solution to the drought, but rather part of the measures to mitigate the water stress suffered by the country.
“You can’t have [la estimulación de lluvias] as a single line of work, it is an integral strategy and a complement to different programs”, he assures.
The country, he continues, must prepare for scenarios of greater water scarcity in the near future: “We believe that in the future, irrigating with crystal clear water will be a luxury.”
BBC
Remember that you can receive notifications from BBC News World. Download the latest version of our app and activate them so you don’t miss out on our best content.
#bombardment #clouds #Mexico #drought #effective