Editing Lake Chad (section)

==Geography==
[[File:Charirivermap.png|thumb|275px|Map showing the Chari River drainage basin|left]]
The Chad Basin includes [[Chad]], Nigeria, [[Cameroon]], Niger, [[Sudan]], and the [[Central African Republic]].<ref>{{cite web|url=https://cblt.org/wp-content/uploads/2021/06/about-map.jpg|title=about-map|access-date=2024-03-26|work=Lake Chad Basin Commission}}</ref> It is an extensional fault depression type [[rift basin]], which can be divided into four secondary [[structural unit]]s: southern depression, northern depression, central uplift, and eastern slope. The southern depression of the basin is characterized by an asymmetric fault depression composite rift with steep slopes in the east and gentle slopes in the west on the profile, and is distributed in an NNW direction on the plane. There are two large basin‐bounding normal [[fault (geology)|fault]] developed on both sides of the basin, with a [[graben]] style fault and [[depression (geology)|depression]] in the middle. The east and west sides are outward dipping low angle gentle slope areas. The eastern boundary fault is steep with a dip angle of about 55°, while the western fault has a dip angle of about 45°. The overall thickness of the inner layer in the slope area is relatively thin. In the central area of the basin, the thickness of the sedimentary strata is large, and the thickness of the sedimentary center zone reaches over {{convert|10000|m|ft|abbr=on}}. The northern part of the basin appears steep in the west and gentle in the east on the profile. Five fault structural zones parallel to the basin‐bounding faults have developed from west to east.<ref>{{cite journal |title=乍得湖盆地构造特征与油气成藏规律初探 |trans-title=A preliminary study on the tectonic characteristics and hydrocarbon accumulation law of the Lake Chad Basin |author1=黄先雄|author2=夏斌|author3=万志峰|author4=吕宝凤|author5=蔡周荣|journal=大地构造与成矿学 |url=https://doi.org/10.16539%2Fj.ddgzyckx.2008.03.013|date=2008 |issue=3 |pages=326–331 |doi=10.16539/j.ddgzyckx.2008.03.013}}</ref>

Lake Chad is divided into north and south parts by a shallow sill called the Great Barrier, with the bottom of the northern basin at an altitude of {{convert|275.3|m|ft|abbr=on}} and the bottom of the southern basin at {{convert|278.2|m|ft|abbr=on}}. When the water level in the south exceeds {{convert|279|m|ft|abbr=on}} above sea level, it will flow into the north.<ref name=7g/> In the south, there is continuous open water at the mouth of the Chari River, and the western part of the water is covered by reed swamps,<ref name=h8>{{cite journal |author1=Marie-Thérèse Sarch |author2=Charon Birkett |title=Fishing and farming at Lake Chad: Responses to lake-level fluctuations |journal=The Geographical Journal |date=June 2000 |volume=166 |issue=2 |pages=156–172 |jstor=823109 |url=https://www.jstor.org/stable/823109 |access-date=2023-06-18 |archive-date=2023-06-18 |archive-url=https://web.archive.org/web/20230618010146/https://www.jstor.org/stable/823109 }}</ref> and the sand dunes that are not completely submerged in the eastern waters form an archipelago.<ref name=r4/> The average depth of the southern lake basin is between {{convert|.5|and|2|m|ftin|abbr=on}}, that of the northern lake basin is between 0 and {{convert|1.8|m|ftin|abbr=on}}, and that of the eastern archipelago is between 0 and {{convert|2|m|ftin|abbr=on}}.<ref>{{cite journal |author1=Jacques Lemoalle |author2=Jean-Claude Bader |author3=Marc Leblanc |author4=Ahmed Sedick |title=Recent changes in Lake Chad: Observations, simulations and management options (1973–2011) |journal=Global and Planetary Change |date=January 2012 |volume=80–81 |issue=247–254 |pages=247–254 |doi=10.1016/j.gloplacha.2011.07.004}}</ref>

The climate of the Lake Chad region is strongly influenced by continental and maritime [[air mass]]es. The maritime air mass moves northward during the summer, producing seasonal precipitation. In late summer, continental air mass dominate again.<ref name=w2/> The average annual precipitation in the Lake Chad area is {{convert|330|mm|in|0|abbr=on}}, with an average annual precipitation of {{convert|560|mm|in|1|abbr=on}} on the south bank and about {{convert|250|mm|in|1|abbr=on}} on the north bank. The highest temperature in the rainy season is {{cvt|30|C|F}}, and the highest temperature rises to more than {{convert|32|C|F|abbr=on}} when October and November enter the dry season. The temperature difference between day and night is almost twice that of the rainy season, and the lowest nighttime temperature sometimes drops to {{convert|8|C|F|abbr=on}} in December and January. April is usually the hottest month of the year, with temperatures occasionally reaching {{convert|40|C|F|abbr=on}}, the lowest water levels appear in June to July, and the highest water levels in November to December, with surface water temperatures ranging from {{convert|19|to|32|C|F|abbr=on}}.<ref name=w2>{{cite encyclopedia |last1=Gritzner |first1=J. A. |title=Lake Chad |encyclopedia=Encyclopedia Britannica |location=Chicago |publisher=Encyclopædia Britannica, Inc. |url=https://www.britannica.com/place/Lake-Chad |accessdate=2023-06-13 |language=en |archive-date=22 July 2019 |archive-url=https://web.archive.org/web/20190722235543/https://www.britannica.com/place/Lake-Chad |url-status=live }}</ref><ref name=r4/>