Yemen occupies the southern end of the Arabian Plate. The country's mountainous interior is surrounded by narrow coastal plains to the west, south, and east and by upland desert to the north along the border with Saudi Arabia. The Tihamah is a nearly long, semidesert coastal plain that runs along the Red Sea and is part of the Arabian Peninsula coastal fog desertecoregion. The highland regions are interspersed with wadis, or river valleys, that are dry in the winter months Most notable is the Wadi Hadhramaut in eastern Yemen, the upper portions of which contain alluvial soil and floodwaters and the lower portion of which is barren and largely uninhabited. Both the eastern plateau region and the desert in the north are hot and dry with little vegetation. In the northeastern Empty Quarter, sands highlight the region, being the largest expanse of sand in the world. It receives little to no rain for extensive periods of time. Little vegetation grows here either. The central highlands are drier than the western highlands because of rain-shadow influences, but still receives sufficient rain in wet years for extensive cropping. Its diurnal temperature variations are among the highest in the world: ranges from in the day to at night are normal. Water storage allows for irrigation and the growing of wheat and barley while the western highlands are famous for sorghum, coffee, and some tropical fruits like bananas and mangos.
Elevation
Yemen is a continuously elevated country, with only the coastal plains being the lowest-lying areas. Jagged peaks and plateaus cover most of Yemen, and the average elevation in the country is about. The interior mountains have elevations ranging from a few hundred meters to the highest point in the country and the Arabian Peninsula, Jabal An-Nabi Shu'ayb, which is above sea level, within the Harazi subrange of the Sarawat. The range of elevation is thus from sea level to, and among the countries in the Arab world, it is the one with the second highest high point, after Morocco's high Jbel Toubkal. The Yemenis used the elevation of their homeland to stay isolated for thousands of years with foreign trade conducted only when the Yemenis wished to go to the coastal areas. The mountains are young, jagged peaks that are known to rise from an elevation of a few hundred meters to well over. The mountains can be separated into a western and central highland. The western highlands have peaks reaching around, with relatively fertile soil and sufficient and plentiful rainfall. The central highlands is more like a plateau of about, with rolling hills, small knolls, and some very prominent peaks, but is still relatively more elevated. Less rainfall can be seen in this region, but the summer months give enough to sustain crops.
Climate
Temperatures are more pleasant in Yemen than other arab countries due to high elevation. Rainfall is varied based on elevation. The highlands enjoy a temperate, rainy summer with an average high temperature of and a cool, moderately dry winter with temperatures occasionally dipping below. The climate of the Tihamah is tropical; temperatures occasionally exceed, and the humidity ranges from 50 to 70 percent. Rainfall, which comes in irregular heavy torrents, averages annually. In Aden the average temperature is in January and in June, but with highs often exceeding. Average annual rainfall is. The highest mountainous areas of southern Yemen receive from of rain a year. Some areas of the western highlands, most notably Ibb and Ta'izz, receive from about of rain each year. The capital, Sana'a, receives around a year, it is not uncommon for the northern and eastern sections of the country to receive no rain for five years or more. The Wadi Hadhramaut in the eastern part of Yemen is arid and hot, and the humidity ranges from 35 percent in June to 64 percent in January. Yemen has the most fertile land in the Arabian peninsula.
Coastline and maritime claims
Yemen has of coastline along the Arabian Sea, the Gulf of Aden, and the Red Sea. Yemen claims a territorial sea of, a contiguous zone of, an Exclusive Economic Zone of based on. It has a continental shelf of or to the edge of the continental margin.
Natural resources
Yemen's principal natural resources are oil and natural gas as well as agriculturally productive land in the west. Other natural resources include fish and seafood, rock salt, marble, and major unexplored deposits of coal, gold, lead, nickel, and copper.
Land use
Only 2.91 percent of Yemen is considered to be arable land, and less than 0.6 percent of the land is planted with permanent crops. About of the land is irrigated. According to the United Nations, Yemen has of forest and other wooded land, which constitutes almost 4 percent of total land area.
A long-standing dispute between Saudi Arabia and Yemen was resolved in June 2000 with the signing of the Treaty of Jeddah. This agreement provides coordinates for use in delineating the land and maritime border, including the section in the eastern desert region of Yemen that potentially contains significant amounts of oil. Friction between the two countries in recent years over security of the borders appears to have been alleviated by the establishment of joint border patrols. Following years of dispute between Yemen and Eritrea over ownership of the Hanish Islands and fishing rightsin the Red Sea, in 1999 an international arbitration panel awarded sovereignty of the islands to Yemen. Relations between the two countries remain strained, however, and Yemen continues to protest Eritrean fishing in the disputed territory.
