255
It must be considered that MSL records are modified by geologic processes, due
to the convergence of tectonic plates (Wyss 1976; Albrecht and Shaffer 2016).
Within seismic cycle, co-seismic (during earth quake) and inter-seismic (between
earth quakes) movements result in coastal raising or subsidence. Cases where the
instrumental record shows descend of NSL can indicate the tide gauge is being
raised faster than the MSL raising caused by climate change. Co-seismic vertical
movements can produce descend of meters in the MSL (e.g. Farías et al. 2010),
which equals centuries of raising associated to climate change.
MSL is also affected by irregular cyclic oscillations like ENSO. Contreras et al.
(2012) observed that ENSO can increase MSL monthly averages up to 30 cm during
El Niño and reduce these values in the same order during La Niña. The increase of
Monthly rainfall in Rapel
500
400
300
200
100
0
3
2
-1
-2
1
0
ONI
(mm)
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Fig. 8.5 Monthly precipitations in Rapel (1940–2016) and Oceanic Niño Index (ONI) (1950–
2016). A negative lineal trend for precipitations fitted by means of minimum squares is also shown.
Large intra-annual variations in precipitation can be explained by variations of ONI
Monthly discharge Maipo River
1980
0
200
400
600
800
1985
1990
1995
2000
2005
2010
2015
(m
3
s
-1
)
Fig. 8.6 Monthly river discharge (m
3 s
−1
) at Maipo river mouth between 1939 and 2012. The
higher swellings correspond to years 1987/1988 and 2002/2003, which do not correspond to
intense ENSO events. On the other hand, ENSO 1982/1983 and 1997/1998 have associated important swellings but not as severe as those observed during 1987/1988 y 2002/2003
8 El Yali National Reserve: A System of Coastal Wetlands in the Southern…
It must be considered that MSL records are modified by geologic processes, due
to the convergence of tectonic plates (Wyss 1976; Albrecht and Shaffer 2016).
Within seismic cycle, co-seismic (during earth quake) and inter-seismic (between
earth quakes) movements result in coastal raising or subsidence. Cases where the
instrumental record shows descend of NSL can indicate the tide gauge is being
raised faster than the MSL raising caused by climate change. Co-seismic vertical
movements can produce descend of meters in the MSL (e.g. Farías et al. 2010),
which equals centuries of raising associated to climate change.
MSL is also affected by irregular cyclic oscillations like ENSO. Contreras et al.
(2012) observed that ENSO can increase MSL monthly averages up to 30 cm during
El Niño and reduce these values in the same order during La Niña. The increase of
Monthly rainfall in Rapel
500
400
300
200
100
0
3
2
-1
-2
1
0
ONI
(mm)
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Fig. 8.5 Monthly precipitations in Rapel (1940–2016) and Oceanic Niño Index (ONI) (1950–
2016). A negative lineal trend for precipitations fitted by means of minimum squares is also shown.
Large intra-annual variations in precipitation can be explained by variations of ONI
Monthly discharge Maipo River
1980
0
200
400
600
800
1985
1990
1995
2000
2005
2010
2015
(m
3
s
-1
)
Fig. 8.6 Monthly river discharge (m
3 s
−1
) at Maipo river mouth between 1939 and 2012. The
higher swellings correspond to years 1987/1988 and 2002/2003, which do not correspond to
intense ENSO events. On the other hand, ENSO 1982/1983 and 1997/1998 have associated important swellings but not as severe as those observed during 1987/1988 y 2002/2003
8 El Yali National Reserve: A System of Coastal Wetlands in the Southern…