Tropical cloud clusters (TCC) play a vital role in Earth's climate by not only releasing a large amount of latent heat into the atmosphere but also by forming the basis for the development of tropical cyclones (TC). However, not all TCCs can develop into cyclones; only a few develop into TC selectively. There are large uncertainties in the current understanding of why only certain TCCs develop into TC while others don't. The present study employs global TCC observations generated by GridSat and IBTrACS datasets from 1980 to 2009 to investigate the TCC distributions over various Oceanic basins such as the North Atlantic (NA), South Atlantic (SA), East-West and South Pacific (EP, WP and SP), as well as the North Indian (NI) and South Indian (SI) basins. The central objective of the present study is to characterize the size spectrum of TCCs and investigate their potential transformation into TCs. The TCCs are identified based on different IR temperature thresholds in each basin. The present results suggest that ∼ 5.5 % of TCCs were developed into TCs annually globally, and their trends in each oceanic basin are discussed. The size spectrum of TCCs showed a dominant peak at 100–200 km². About 48 % of TCCs transform into TCs within 24 hr of being identified. Furthermore, 85 % of TCCs develop into TCs within 84 hr of the first identification, while only 5 % of TCCs develop into TCs after 84 hr. Further, we have also analyzed the background environmental conditions such as low-level wind speed, vorticity, divergence, vertical shear, upper-level relative humidly and latent heating (LH) for developing and non-developing TCCs over the NI basin, which have not been explored in detail in earlier studies. It is noted that the relative humidity in the developing composite is around 10–20 % higher than that in non-developing TCCs, and LH in developing TCCs is 0.15 K/hr, larger than that in non-developing TCCs. The significance of the present study lies in investigating the developing TCCs as a function of their size and lifetime, including their long-term trends, and bringing out favourable environmental conditions for developing TCCs in the NI Ocean.

热带云团（TCC）在地球气候中发挥着至关重要的作用，不仅向大气释放大量潜热，而且形成热带气旋（TC）发展的基础。然而，并非所有TCC都能发展成气旋；只有少数选择性地发展为TC。目前对于为什么只有某些 TCC 发展成为 TC 而其他 TCC 却没有发展成 TC 的理解存在很大的不确定性。本研究利用 GridSat 和 IBTrACS 数据集从 1980 年到 2009 年生成的全球 TCC 观测结果来调查北大西洋 (NA)、南大西洋 (SA)、东西向和南太平洋 (EP, WP 和 SP），以及北印度 (NI) 和南印度 (SI) 盆地。本研究的中心目标是表征 TCC 的尺寸范围并研究它们转化为 TC 的潜力。TCC 是根据每个盆地不同的红外温度阈值来识别的。目前的结果表明，全球每年约有 5.5% 的 TCC 发展成为 TC，并讨论了它们在每个大洋盆地的趋势。^{TCC的尺寸谱在100-200 km 2}处显示出主峰。大约 48% 的 TCC 在被识别后 24 小时内转化为 TC。此外，85%的TCC在首次鉴定后84小时内发育为TC，而只有5%的TCC在84小时后发育为TC。此外，我们还分析了NI盆地发育和非发育TCC的低层风速、涡度、辐散度、垂直切变、高层相对湿度和潜热(LH)等背景环境条件，早期研究中并未详细探讨。值得注意的是，正在发育的复合材料中的相对湿度比非正在发育的TCC中的相对湿度高约10-20%，并且正在发育的TCC中的LH为0.15K/hr，大于非正在发育的TCC中的LH。本研究的意义在于调查正在发育的TCCs与其大小和寿命的关系，包括其长期趋势，并为北非洋TCCs的发育提供有利的环境条件。