6 a) shows an increasing trend through the northwest-southeast trending Zagros Mountain region, across much of the Caspian coast and through into the driest part of the country, the hyperarid southeast.
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Desertification of Iran in the early twenty-first century: assessment using climate and vegetation indices.
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The sentences
A significant trend is indicated when the p -value is < 0.1.
Dissociating the trends by season, however, yields some limited, but highly significant, evidence of change over the study period.
Even if annual temporal changes may not be significant, they may mask important seasonal changes in both drivers and outcomes of desertification, and nationwide syntheses may prove an over-simplification of considerable local and regional variance in landscape stimuli and response.
In each, a positive trend in vegetation during the period 2001–2015 is observed for the northwest of the country (the region with the most temperate climate presently), and a stationary (NPP- and LAI-derived) or increasing (NDVI-derived) trend in vegetation for the far southeast (presently the most arid region of the country).
It is worth noting that the winter precipitation (P) trend during the period 2001–2015 however, is negative, and lies only just outside significance at 95% confidence; spring and summer are non-significant declines.
Short-term excursions are also evident in the LST record, which registered a decreasing trend in winter, summer, and spring between 2001 and 2004 with temperature reductions of 2.7 °C, 4.4 °C, and 1.3 °C, respectively.