Ocean-atmosphere interactions in the North Indian Ocean play a vital role in the onset, progression and withdrawal of the Indian monsoon. This paper describes the Ocean Observation System (OOS), an operational observational programme of the Earth System Science Organization and the National Institute of Ocean Technology (ESSO-NIOT) under India's Ministry of Earth Sciences (MoES). Since 1997 it has provided oceanographic and surface meteorological data in real time for weather forecasting, climate research and several other applications. The programme focuses on understanding the phenomenon of the mean seasonal cycle of the Indian monsoon, the intra-seasonal to intra-decadal oscillations of air-sea interactions, trends that are related to tropical cyclones and the annual cycle balance in the exchange of waters between the two limbs of North Indian Ocean, i.e. the Arabian Sea and the Bay of Bengal. In situ observations are also used to develop, initialise and validate regional forecast models that provide high resolution data. There is also a growing need to understand the spatial phenomenon of oceans using satellite observations, wherein the quality of data needs to be validated and verified carefully. This paper also provides an overview of the scientific and societal impact of the Indian moored buoy network over two decades of operation. ARTICLE HISTORYHistorically, ocean surface measurements have been made via ships of opportunity, cargo vessels that sail the oceans to conduct maritime trade. These measurements were made for the safety of the ships' navigation,

Lung cancer is the leading cause of cancer‐related deaths worldwide (1.76 million deaths in 2018) and the leading cause of brain metastatic disease among all primary cancers. As tumor cells colonize the neuroparenchyma, they breach the tightest and most effective vascular barrier in the body, the blood‐brain barrier (BBB). The functional components of the BBB include endothelial cells, basement membranes, pericytes and astrocytes. Herein, we hypothesized that dynamic transformation of the BBB to the blood‐tumor barrier (BTB) would correlate with changes in paracellular permeability. An experimental model of lung cancer brain metastases was developed using twelve 6‐week‐old athymic nude mice. Mice were injected with 250,000 brain‐seeking cells, which colonized the brain for 4–6 weeks. Animals were injected with 3 kd Texas Red dextran at the time of euthanasia, and brains were harvested, cryosectioned and prepared for immunofluorescence analysis. Metastatic tumors were characterized as highly or poorly permeable based on the diffusion of Texas Red dextran within and around the tumor parenchyma. Brain metastases were roughly spherical and measured between 50–500 μm in diameter, irrespective of their permeability status. The most striking BTB pathology was identified in tight junctions and associated adapter proteins. Highly permeable tumors exhibited haphazard expression of claudin‐5 and a loss of zona occludens‐1 adapter protein compared to metastases with low paracellular permeability. Understanding the cellular and molecular alterations occurring within the BBB during brain metastatic disease from non‐small cell lung cancer is imperative for the identification of novel therapeutic targets and improved methods of drug delivery. Support or Funding Information Claudine Auld was supported by the Summer Research Opportunities Program, sponsored by the American Society of Investigative Pathology. This research was supported in part by the Showalter Research Trust.