Scientists, since a long time, have paid attention on climate change and, in particular, rainfall decrease. These changes have resulted in modifications of the rainfall regime in many Mediterranean regions. This work is based on monthly rainfall data from 17 stations located in the Tafna catchment (North West of Algeria). The study aim is to identify long-term (1970–2016) spatial and temporal trends in annual, seasonal and monthly precipitation, using the innovative trend analysis (ITA) method. The approach is used to classify trends into “low”, “medium”, “high”, which should be taken in consideration in future studies on floods (“high”) and drought (“low”). The monthly rainfall shows a decreasing trend in all studied stations (100% of stations) during February, March, April, and May, the same phenomenon observed in the majority of stations for June, July (82% of stations), and December (58% of stations). Seasonal analysis indicates a downward trend in winter and spring. Using annual rainfall, the stations located in the north, west and central part of the Tafna show a decrease in rainfall (59% of stations).

长期以来，科学家一直关注气候变化，尤其是降雨减少。这些变化导致许多地中海地区的降雨状况发生了变化。这项工作基于位于塔夫纳集水区（阿尔及利亚西北部）的17个气象站的月降雨量数据。研究的目的是使用创新趋势分析（ITA）方法确定年，季节性和月降水量的长期（1970–2016）时空趋势。该方法用于将趋势分为“低”，“中”，“高”，在以后的洪水（“高”）和干旱（“低”）研究中应考虑这些趋势。在2月，3月，4月和5月，所有已研究站点（占站点的100％）的月降雨量均呈下降趋势，在6月，7月（占总站数的82％）和12月（占总站数的58％）的大多数站点中都观察到了相同的现象。季节性分析表明，冬季和春季呈下降趋势。使用年降水量，位于塔夫纳河北部，西部和中部的气象站的降雨量减少了（占气象站的59％）。