Moderate-Resolution Imaging Spectroradiometer in the context of "Aqua (satellite)"

Derbent, also historically known as Darband, or Derbend, is the southernmost city in Russia. It is situated along the southeastern coast of the Republic of Dagestan, occupying the narrow gateway between the Caspian Sea and the Caucasus Mountains, and connecting the Eurasian Steppe to the north and the Iranian Plateau to the south. Derbent covers an area of 69.63 square kilometres (26.88 sq mi) with a population of roughly 120,000 residents.

Derbent is considered the oldest city in Russia, with historical documentation dating to the 8th century BC, making it one of the oldest continuously inhabited cities in the world. Due to its strategic location, over the course of history, the city changed ownership many times, particularly among the Persian, Arab, Mongol, Timurid, and Shirvan kingdoms. In the early 19th century, the city came under control of the Russian Empire through the Treaty of Gulistan signed with Qajar Iran.

Total organic carbon (TOC) is an analytical parameter representing the concentration of organic carbon in a sample. TOC determinations are made in a variety of application areas. For example, TOC may be used as a non-specific indicator of water quality, or TOC of source rock may be used as one factor in evaluating a petroleum play. For marine surface sediments average TOC content is 0.5% in the deep ocean, and 2% along the eastern margins.

A typical analysis for total carbon (TC) measures both the total organic carbon (TOC) present and the complementing total inorganic carbon (TIC), the latter representing the amount of non-organic carbon, like carbon in carbonate minerals. Subtracting the inorganic carbon from the total carbon yields TOC. Another common variant of TOC analysis involves removing the TIC portion first and then measuring the leftover carbon. This method involves purging an acidified sample with carbon-free air or nitrogen prior to measurement, and so is more accurately called non-purgeable organic carbon (NPOC).