Episodic events are increasing in Bangladesh, in the last decade compared to historical data

Episodic events are increasing in Bangladesh, in the last decade compared to historical data

Tropical cyclone formation is influenced by many factors. The changes in the intensity, frequency and distribution of tropical cyclone increases due to anthropogenic changes in the composition of the atmosphere along with the warmer sea-surface temperatures which increases the probability of stronger cyclones formation.

The projection of tropical cyclone also depends on the type of data availability i.e., high resolution models with current data can generate realistic cyclone data in some aspects, but less so in other aspects. As we increase the model resolution we can get even better results – but this is dependent on inputting the correct climate data.

In the recent article “Changes in tropical cyclones under stabilized 1.5 and 2.0 ◦C global warming scenarios as simulated by the Community Atmospheric Model under the HAPPI protocols” made by the Wehner, et al., 2018, have projected the future tropical cyclone statistics and showed that at low warming levels the most intense tropical cyclones become more frequent and more intense, while simultaneously the frequency of weaker tropical storms is decreased.

https://www.earth-syst-dynam.net/9/187/2018/esd-9-187-2018.pdf

"Whether the characteristics of tropical cyclones have changed or will change in a warming climate — and if so, how — has been the subject of considerable investigation, often with conflicting results. Large amplitude fluctuations in the frequency and intensity of tropical cyclones greatly complicate both the detection of long-term trends and their attribution to rising levels of atmospheric greenhouse gases. Trend detection is further impeded by substantial limitations in the availability and quality of global historical records of tropical cyclones. Therefore, it remains uncertain whether past changes in tropical cyclone activity have exceeded the variability expected from natural causes. However, future projections based on theory and high-resolution dynamical models consistently indicate that greenhouse warming will cause the globally averaged intensity of tropical cyclones to shift towards stronger storms, with intensity increases of 2–11% by 2100. Existing modelling studies also consistently project decreases in the globally averaged frequency of tropical cyclones, by 6–34%. Balanced against this, higher resolution modelling studies typically project substantial increases in the frequency of the most intense cyclones, and increases of the order of 20% in the precipitation rate within 100 km of the storm centre. For all cyclone parameters, projected changes for individual basins show large variations between different modelling studies. " (Knutson et al. 2010)

There is higher consensus though that with rising temperature trends due changing climate the atmospheric moisture holding capacity would increase which is proclaimed to raise the intensity of such extreme weather events like that of a cyclone.

Intensity of tropical cyclones will be variably influenced by climate change while warm surface temperature of the ocean shall favour cyclone intensification , weak temperature gradient shall decrease the possibility of cyclone formation. High resolution modelling studies show there may be decrease in frequency of tropical cyclone but an increase in high intensity cyclones.

It is expected that an evident changes will observe in tropical cyclone intensity, frequency and distribution as the climate warms due to anthropogenic changes in the composition of the atmosphere. According to IPCC AR5 the tropical cyclone intensities will globally likely increase on average and sea-level rise due to anthropogenic interventions should be causing higher storm surge levels for tropical cyclones. Tropical cyclones are of particular consequence for extreme high sea-levels and in parts of some cyclone-prone basins, more than 75% of annual sea- level maxima are found to be linked to tropical cyclones (Khouakhi et. al, 2017). Tropical cyclone rainfall rates will likely increase in the future in order of 10-15% for rainfall rates averaged within about 100 km of the storm for a 2-degree Celsius global warming scenario. For a warming of about 2.5°C by the end of the century, occurrence probabilities of Category 4 or 5 cyclones are found to increase substantially (Knutson et. al, 2015).

The paper by Webster et al. (2005) concludes, "that global data indicate a 30 year trend toward more frequent and intense hurricanes, corroborated by the results of the recent regional assessment (29). This trend is not inconsistent with recent climate model simulations that a doubling of CO2 may increase the frequency of the most intense cyclones (18, 30), although attribution of the 30 year trends to global warming would require a longer global data record and, especially, a deeper understanding of the role of hurricanes in the general circulation of the atmosphere and ocean, even in the present climate state."

Hence, it emphasizes the need to incorporate longer global data record and, with better understanding of role of cyclones in the GCMs dealing with atmosphere-ocean interface processes.

No, because climate change has not yet been proven unambiguously.

I don't know about satellite data, but Earth station data have a quality that tends to garbage, after year 1969, monotonously, see here for details:

Article Extraction of the global absolute temperature for Northern H...

And probably the news industry makes things worse...

Recently we had a small cyclone in the sea between Italy Greece and Libya which upon coming to land was a low pressure system.

Well we had been bombarded for days about "cyclone" and again "cyclone"...

(People from USA would laugh since it was not neither 1 in the scale of typhoons.)

And that was the daily news agent for days.

Conclusions are yours...

Hi Rajesh, I think your question is related with my recent discussion:

https://www.researchgate.net/post/What_factors_affect_the_number_of_tropical_storms_on_the_earth

It might be helpful if you combine the answers here with my discussion.

You can watch this week, as the Cyclone Fani, instead of making landfall in the middle of India, is getting pushed by the wall of the Pakistan-Arabia Dust Cloud at 120 degrees off track towards the NE, to smack right in the center of Bangladesh. You can see from comparing the daily NAAPS (dust cloud images with the storm track, that it only takes 20-40 micrograms of atmospheric dust per cubic meter, to make a tropical cyclone change its path? Instead, if we eliminate the atmospheric dust clouds, by replanting those areas with local native plants, then we could have the rain clouds come back naturally, and direct the rainfall from cyclones to desert areas, rather than create floods for the people of Bangladesh later on this week?

Here is what the Dust Cloud vs Cyclone battle looks like today on the http://rammb.cira.colostate.edu/products/tc_realtime/index.asp website