Table:
Cumulonimbus Cloud
Abbreviation	Cb
Genus	Cumulonimbus (heaped, rain)
Species

Calvus
Capillatus

Variety	None
Altitude	500-16,000 m
(2,000-52,000 ft)
Classification	Family C (Low-level)
Appearance	Very tall and large clouds
Precipitation cloud?	Very common, heavy at times

Different merged cells often exist in a table and they can be represented by the JSON {'top-left':(x, y), 'bottom-right':(m, n)}. In this JSON item, '(x, y)' and '(m, n)' are the (row_id, column_id) coordinates for the top-left and bottom-right cells in the merged region, respectively. Please examine the provided table image, identify all merged cells, and return their details using the above-mentioned format. Remember, the numbering for both rows and columns starts at 1.

The merged cell area is: {'top-left':(1, 1), 'bottom-right':(1, 2)}.