Lokacin zafi na tsakiyar Piacenzian

Lokacin zafi na Mid-Piacenzian (mPWP) (kafin 2009 da aka sani da Lokacin zafi ), ko kuma mafi girman zafi na Pliacene, lokaci ne na yanayi mai dumi a lokacin zamanin Pliocene wanda ya kasance daga shekaru miliyan 3.3 zuwa 3.0 da suka gabata (Ma). 

 Yanayi 
Matsakaicin zafin jiki na duniya a tsakiyar-Pliocene ya kasance 2-3 ° C mafi girma fiye da yau,  matakin teku na duniya mita 25 mafi girma,  kuma kankara na Arewacin Hemisphere ya kasance na ɗan lokaci kafin farawar babban glaciation a kan Greenland wanda ya faru a ƙarshen Pliocene a kusa da 3 Ma.  Yankin permafrost na kusa da ƙasa ya kasance ƙasa da na yanzu. Ruwan sama na duniya ya karu da 0.09 mm / shekara bisa ga kwaikwayon CCSM4. An raunana yaduwar Hadley ta Arewa ta shekara-shekara, amma an inganta yaduwar hadley ta Kudancin shekara-sheko. Kamar yadda a lokacin Quaternary glaciation, zagaye na glacial-interglacial ya wanzu a lokacin mPWP kuma ba daidaituwa ba ne kuma yanayin yanayi.

Ƙarin ƙwayoyin cuta a lokacin mPWP ya kasance mai yawa. Matsakaicin zafin jiki na shekara-shekara (MAT) na gabashin Alaska ya kasance kusan 7-9 ° C sama da MAT na yanzu na -6.4 ° C. Shaidar palynological daga Yermak Plateau a cikin Tekun Arctic ta nuna cewa al'ummar Tsuga-Thuja--Betula-Ilex masu zafi da zafi sun zama masu rinjaye a cikin Arctic a lokacin mPWP. A lagerstatte na Camp del Ninots a arewa maso gabashin Spain, MAT na 14.3 ± 2.6 °C da matsakaicin ruwan sama na shekara-shekara (MAP) na 846.8 ± 165.4 mm sun mamaye. Gabashin Asiya Winter Monsoon (EAWM) ya ƙarfafa a lokacin mPWP. Tasirin Gabashin Asiya Summer Monsoon (EASM) bai kai har zuwa cikin Gabashin Asiya ba kamar yadda yake a yau, wanda ya haifar da yanayin da ya fi bushewa ya faru a cikin Loess Plateau na kasar Sin dangane da yau. A cikin Nihewan Basin, yanayi mai ɗorewa da dumi ya fi yawa daga 3.58 Ma zuwa 3.31 Ma. Daga 3.31 Ma zuwa 3.10 Ma, zafi ya ci gaba amma tare da rashin daidaituwa mafi girma, tare da manyan abubuwan sanyi guda uku da ke faruwa a wannan lokacin. Bayan 3.10 Ma, yanayin yankin ya sanyaya sosai. A cikin Qaidam Basin, ruwan sama na shekara-shekara ya kasance kusan sau goma fiye da na yanzu, kuma ya bambanta a cikin zagaye na 20 kuma mai yiwuwa yana da alaƙa da canjin EASM don mayar da martani ga yanayin kankara na Antarctic da tilasta insolation. Kuroshio Current Extension (KCE) ya koma arewa. Kudancin Asiya Summer Monsoon (SASM) ya zama mai ƙarfi a matakin yanki da na meridional. A kudancin Afirka, yankunan ruwan sama na rani da na hunturu sun sauya zuwa pole zuwa ~ 1 °, yayin da ruwan sama ya ragu da kusan 0.5 mm / rana. Yankin tekun Ecuador ya zama mai bushe. Yankin Afirka ta Kudu na subtropical ya mamaye fynbos da tsire-tsire na gandun daji. 

An kiyasta yawan Carbon dioxide a lokacin Pliocene na Tsakiya a kusan 400 ppmv daga 13/12 rabo a cikin kwayoyin ruwa  da kuma yawan burbushin ganye,  kodayake an ba da ƙididdigar ƙasa tsakanin 330 da 394 ppm a duk lokacin mPWP da 391 ppm a cikin KM5c interglacial, a lokacin mafi zafi na mPWP.
Ana ɗaukar mPWP a matsayin mai yiwuwa na yanayin yanayi na gaba. Ƙarfin hasken rana da ya kai duniya, yanayin duniya, da kuma yawan carbon dioxide sun yi kama da na yanzu. Bugu da ƙari, yawancin nau'o'in tsakiyar Pliocene suna nan, suna taimakawa wajen daidaitawa da wakilai yanayin yanayi. Misali na samfurin yanayi na tsakiyar-Pliocene yana samar da yanayi mai zafi a tsakiyar da kuma high latitudes, kamar yadda 10-20 ° C ya fi zafi fiye da yau sama da 70 ° N. Har ila yau, suna nuna ƙananan bambancin zafin jiki a cikin wurare masu zafi. Biomes na samfurin suna da daidaituwa tare da bayanan palaeobotanical na Pliocene wanda ke nuna canjin arewacin tundra da taiga da fadada savanna da gandun daji mai zafi a Afirka da Ostiraliya. An nuna karuwar tsananin guguwa na wurare masu zafi a lokacin mPWP a matsayin shaida cewa karuwar irin wannan guguwa za ta faru yayin da ake ci gaba da dumamar yanayi. 

 Dubi kuma 

 Pliocene
 El Niño
 Shekaru Miliyan Biyar na Canjin Yanayi

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