Deforestation‐induced reduction in rainfall
Deforestation‐induced reduction in rainfall
复制标题
DOI：
10.1002/hyp.10060
复制
发表时间：
2013-12
影响因子：
3.2
通讯作者：
T. Kumagai;H. Kanamori;T. Yasunari
中科院分区：
文献类型：
--
作者：
T. Kumagai;H. Kanamori;T. Yasunari
版权所有©2013 John Wiley&Sons，Ltd.婆罗洲是世界第三大岛屿，以其雄伟的雨林而闻名(图1a)。东南亚热带森林的相对砍伐率是世界上最高的(Canadell等人，2007年)。20世纪50年代，婆罗洲80%以上的土地面积被原始森林覆盖；然而，高砍伐率(1.7%年)几乎是整个东南亚地区本已严重砍伐率的两倍，导致目前估计的森林覆盖率约为50%(Langner等人，2007年)(图1b)。自1965年以来，婆罗洲的热带硬木木材产量急剧增加，并在20世纪80年代初达到平台期和最大值(Brookfield和Byron，1990)。尽管由于过度采伐，最近整个婆罗洲的木材产量明显迅速下降，但在过去几十年里，婆罗洲出口的木材比热带非洲和拉丁美洲的总和还要多(Curran等人，2004年)。被归类为“退化森林和再生”、“栽培森林镶嵌”和“干/湿裸土；草原；农业”的土地覆盖面积高达3300万公顷，约占婆罗洲总面积的45%(Langner等人，2007年)。热带森林是全球水文通量的主要来源，因此，这种森林覆盖的变化有可能显著改变全球和区域的气候和水文循环(Nobre等人，1991年；Kanae等人，2001年；Avissar和Werth，2005年)。由于热带雨林存在于生态系统水资源最丰富的地方，水文变化可能显著改变生态模式和过程(Malhi等人，2009年；Phillips等人，2009年；熊海和波尔波拉托，2012年)，进而影响对大气的反馈(Meir等人，2006年；博南，2008年)。婆罗洲严重的森林砍伐和森林退化自然会影响区域水文气候；事实上，婆罗洲的长期每日网格降水数据集(阿佛洛狄特水资源，可通过http://www.chikyu.ac.jp/precip/，Yatagai等人查阅，2012年)显示，1951年至2007年期间降水量大幅下降(图1c)。可以看到1980年代后期降雨量突然减少(图1c)，这与砍伐森林，即木材生产的伐木可能变得密集的时期一致(Brookfield和Byron，1990年；Curran等人，2004年)。此外，应当指出，降雨量的这种减少趋势可能会导致频繁的极端干旱和随后的火灾，导致更严重的砍伐森林和森林退化(van Nieuwstadt和Sheil，2005年；Wooster等人，2012年)。1998年至2010年东太平洋大气水汽汇聚的平均空间分布(使用重新分析和网格化的四维气象数据集、日本25年再分析和可通过JapanMeteorologicalAgencyClimateDataAssimilation获得的http://jra.kishou.go.jp/JRA-25/index_en.html)系统建立)表明，与其他区域相比，婆罗洲的水汽汇聚和辐散较少(图2a)。另一方面，热带降雨测量任务1998年至2010年的卫星测量(美国宇航局戈达德地球科学数据和信息服务中心，可通过http://disc.sci.gsfc.nasa.gov/About-Us获得)显示，与海域相比，西太平洋海洋大陆岛屿上方的降雨量更大，
Copyright © 2013 John Wiley & Sons, Ltd. Borneo is the third largest island in the world and famous for its majestic rainforests (Figure 1a). Southeast Asian tropical forests have the highest relative deforestation rate in the world (Canadell et al., 2007). More than 80% of the total land area of Borneo was covered with pristine forest in the 1950s; however, the high deforestation rate (1.7%year ), which is almost double that of the already intense deforestation rate of the whole Southeast Asian region, has resulted in the current estimation of forest cover being ~50% (Langner et al., 2007) (Figure 1b). Since 1965, production of tropical hardwood timber in Borneo sharply increased and reached a plateau and maximum in the early 1980s (Brookfield and Byron, 1990). Although the recent and rapid decline in timber production has been evident throughout Borneo owing to over-logging, over the past decades, more timber was exported from Borneo than from tropical Africa and Latin America combined (Curran et al., 2004). The land cover area categorized as ‘degraded forest and regrowth’, ‘cultivation forest mosaic’ and ‘dry/wet bare soil; grasslands; agriculture’ reached up to 33 million ha, ~45% of the total area of Borneo (Langner et al., 2007). Tropical forests are a major source of global hydrologic fluxes, and thus, this forest cover change has potential to significantly alter the global and regional climate and hydrologic cycling (Nobre et al., 1991;Kanae et al., 2001; Avissar andWerth, 2005). Because tropical rainforests exist where ecosystem water resources are greatest, the hydrologic changes could significantly alter ecological patterns and processes (Malhi et al., 2009; Phillips et al., 2009; Kumagai and Porporato, 2012), in turn affecting feedback to the atmosphere (Meir et al., 2006; Bonan, 2008). It is a matter of course that the drastic deforestation and forest degradation in Borneo should be anticipated to impact the regional hydro-climate; in fact, the long-term daily grid precipitation datasets (APHRODITE’s Water Resources, available via http://www.chikyu.ac.jp/precip/, Yatagai et al., 2012) over Borneo showed a significant decline in precipitation over the period 1951–2007 (Figure 1c). An abrupt decline in precipitation in the late 1980s can be seen (Figure 1c), which was consistent with a time when deforestation, i.e. logging for timber production, might have become intensive (Brookfield and Byron, 1990; Curran et al., 2004). Furthermore, it should be noted that such a decreasing trend in precipitationmight cause frequent extreme droughts and subsequent fires, resulting in more severe deforestation and forest degradation (van Nieuwstadt and Sheil, 2005; Wooster et al., 2012). A spatial distribution of atmospheric moisture convergence averaged over 1998–2010 in the eastern Pacific Ocean (built using a reanalyzed and gridded four-dimensional meteorology dataset, Japanese 25-year ReAnalysis and the JapanMeteorologicalAgencyClimateDataAssimilation System available via http://jra.kishou.go.jp/JRA-25/index_en.html) suggests less moisture convergence and divergence over Borneo compared with other regions (Figure 2a). On the other hand, the Tropical Rainfall Measuring Mission satellite measurements from 1998 to 2010 (NASA Goddard Earth Sciences Data and Information Services Center, available via http://disc.sci.gsfc.nasa.gov/ about-us) showed a larger amount of precipitation above islands of the maritime continent in the western Pacific Ocean compared with sea areas,