24SMOI The Kavaratti Project: Meteorology Over the Lakshadweep Sea For Climate Simulation

This reports progress following the 2023 AMS meeting, towards the Glitter Belt architecture to address Global Warming via Global Atmospheric Mapping. The overall architecture has now been published in a paper in Applied Energy (Ref.1) , and technical advancement on several components, in various other publications. The overall architecture for sunlight-reflecting mid-stratosphere ultralight HALE (high altitude long endurance) UAV swarms is based on sets of 11 Flying Leaflet (FLT) biplanes. Each biplane carries a reflective sheet of span 32m, joining together in the calm air of 30km altitude to form 352m span Flying Leaves. Eight of 11 FLT wing-propeller-solar-panel assemblies return to base for their next solar-powered launch. The 32m span is selected to give the most span while being convenient to launch from a cricket or baseball field, anywhere in the world on a calm summer morning. With high aspect ratio and yet large area giving low wing loading, the Flying Leaf is able to remain at altitudes between 30.5km during the day and 18.3km at dawn through a 12-hour night, while flying at speeds sufficient to overcome most winds. The 12-hour maximum night is while crossing the Equator, while following annual Peak Summer Sun Follower trajectories over the oceans.

Possible Scaleup From Meteorology to GeoEngineering:

As discussed in Ref. (1), if and when the nations of the world decide that it is safe, based on meteorological data and validated Climate simulations, they can then decide that it is essential to expand to a global system sufficient of sufficient size to reverse atmospheric heat retention. At that level, these swarms might resemble millions of sparse but glittering points of sunlight when viewed from Space, if visible at all. They would not be visible from below, day or night, except for navigation lights if used. This accounts for the Glitter Belt name. In Ref. (1) we show a calculation on what it might take to actually reverse the EEI (a measure of heat retention and hence Global Warming) all the way back to 1990, the original target of the Kyoto Protocol.

Possibility of delaying or reversing Sea Level Rise:

In recent work we have shown initial calculations on a subset called Polar Necklace. This is a stream, or train of reflector vehicles, catching the strong polar circle winds to fly in a manner such as to cause a small decrease in sunlight over the edge of the Antarctic sea ice. By altering the balance between rate of Summer thinning of the ice sheet by melting, and Winter thickening by accumulation, it is possible according to some researchers, to damp out ocean wave action from reaching under the glacier edge overhang. This could keep the glacier edge shelves from cracking and breaking off. Such break-off, such as the collapse of the Ross Ice Shelf some years ago, have a profound effect on sea-level. We postulate that a gradual strengthening of the sea ice could therefore increase the amount of ice captured in Antarctica, sufficiently to delay or even reverse Sea Level Rise, the most visible threat from Global Warming

Present Work:

With the general strategy established in open publications as specified by the National Academies for responsible conduct, we are shifting attention to design, construction and testing of smaller model-scale vehicles. The initial plan was to progress from 2m and 4m vehicles to establish many parameters, to 8m span vehicles for initial over-water testing, then build 16m FLTs that could reach high altitudes, and then deploy full-scale 32m FLTs to form 352m FLs for the global meteorology function.

The Kavaratti Project: An 8m span model has gone through flight simulation to verify stability and performance, and is now going through final structural simulation testing, close to construction. It is designed for meteorological data acquisition up to the Tropopause, over the Lakshadweep Sea off the West Coast of India. Kavaratti, the capital, is the helipad closest to the west coast of Mainland India, being 371 km away. The 8m “Kavaratti” model is to carry instrumentation for vertical wind profiling, and measuring particulates and atmospheric conditions during off-monsoon months. There are two mission windows. From mid January to April the weather is mostly dry all round the southern coast of India. In October through mid-November it is again dry and mostly calm.

The model demonstrates carbon fiber truss construction to achieve very low wing loading. In flight simulation it can fly for a day at 5000 to 11,000 meters altitude, reaching the Lakshadweep from the west coast of mainland India with a comfortable wind margin before sunset (and energy to glide to landing after dark if needed). Payload capacity will be only about 1 to 2kg for each FLT, since vehicle total weight is to stay under 25kg. Preparation includes different models under construction at universities, to test sensor operation, data acquisition and transfer at low altitudes.

New finding: Going global with 8m models. A new finding is that the 8m span vehicles are sufficient, to form a Flying Leaf of 72m span, which is able to stay aloft through a 12 hour night without coming down below 18.3 km, after rising to 31.5km by dusk. This means that deployment of long-duration meteorology vehicles over remote areas can proceed directly after proving the 8m Flying Leaflet (FLTs) vehicles, rather than wait for an extended development cycle where 16m and 32m-span FLTs had to be developed. With this new finding, meteorology and remote sensing applications can proceed very quickly, while mass deployment of vehicles that are optimized to reflect sunlight can wait until Climate Predictions are at sufficient level of confidence.

Acknowledgements: We gratefully acknowledge generous partial support from the Taksha Institute, and use of resources and faculty guidance from Amrita Visa Viyapeetham and IIT Madras.

Concept Picture: Shows a solar-powered Flying Leaflet vehicle being tested in flight simulation at 35700 meters above the East Coast of India (near Chennai) and near Agatti Island, Lakshadweep. The planned Kavaratti Project Routemap is seen at right.