scholarly journals Inter-comparison and assessment of gridded climate products over tropical forests during the 2015/2016 El Niño

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170406 ◽  
Author(s):  
C. Burton ◽  
S. Rifai ◽  
Y. Malhi
Keyword(s):  
Southeast Asia ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Air Temperature ◽  
El Niño ◽  
El Nino ◽  
Congo Basin ◽  
Wide Range ◽  
Spatio Temporal ◽  
The Impact

To understand the impacts of extreme climate events, it is first necessary to understand the spatio-temporal characteristics of the event. Gridded climate products are frequently used to describe climate patterns but have been shown to perform poorly over data-sparse regions such as tropical forests. Often, they are uncritically employed in a wide range of studies linking tropical forest processes to large-scale climate variability. Here, we conduct an inter-comparison and assessment of near-surface air temperature fields supplied by four state-of-the-art reanalysis products, along with precipitation estimates supplied by four merged satellite-gauge rainfall products. Firstly, spatio-temporal patterns of temperature and precipitation anomalies during the 2015–2016 El Niño are shown for each product to characterize the impact of the El Niño on the tropical forest biomes of Equatorial Africa, Southeast Asia and South America. Using meteorological station data, a two-stage assessment is then conducted to determine which products most reliably model tropical climates during the 2015–2016 El Niño, and which perform best over the longer-term satellite observation period (1980–2016). Results suggest that eastern Amazonia, parts of the Congo Basin and mainland Southeast Asia all experienced significant monthly mean temperature anomalies during the El Niño, while northeastern Amazonia, eastern Borneo and southern New Guinea experienced significant precipitation deficits. Our results suggest ERA-Interim and MERRA2 are the most reliable air temperature datasets, while TRMM 3B42 V7 and CHIRPS v2.0 are the best-performing rainfall datasets. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Coping with abrupt environmental change: the impact of the coastal El Niño 2017 on artisanal fisheries and mariculture in North Peru

2018 ◽  
Vol 76 (4) ◽  
pp. 1122-1130 ◽  
Author(s):  
Lotta Clara Kluger ◽  
Sophia Kochalski ◽  
Arturo Aguirre-Velarde ◽  
Ivonne Vivar ◽  
Matthias Wolff
Keyword(s):  
El Niño ◽  
El Nino ◽  
Management Strategies ◽  
Small Scale ◽  
Artisanal Fisheries ◽  
Economic Activities ◽  
Economic Sectors ◽  
Wide Range ◽  
The Impact ◽  
Coastal El Niño

Abstract In February and March 2017, a coastal El Niño caused extraordinary heavy rains and a rise in water temperatures along the coast of northern Peru. In this work, we document the impacts of this phenomenon on the artisanal fisheries and the scallop aquaculture sector, both of which represent important socio-economic activities for the province of Sechura. Despite the perceived absence of effective disaster management and rehabilitation policies, resource users opted for a wide range of different adaptation strategies and are currently striving towards recovery. One year after the event, the artisanal fisheries fleet has returned to operating almost on a normal scale, while the aquaculture sector is still drastically impacted, with many people continuing to work in different economic sectors and even in other regions of the country. Recovery of the social-ecological system of Sechura likely depends on the occurrence of scallop seed and the financial capacity of small-scale producers to reinitiate scallop cultures. Long-term consequences of this coastal El Niño are yet to be studied, though the need to develop trans-local and trans-sectoral management strategies for coping with disturbance events of this scale is emphasized.

Tropical forest dynamics across a rainfall gradient and the impact of an El Niño dry season

2004 ◽  
Vol 20 (01) ◽  
pp. 51-72 ◽  
Author(s):  
Richard Condit ◽  
Salomon Aguilar ◽  
Andres Hernandez ◽  
Rolando Perez ◽  
Suzanne Lao ◽  
...  
Keyword(s):  
Tropical Forest ◽  
El Niño ◽  
Forest Dynamics ◽  
El Nino ◽  
Dry Season ◽  
Rainfall Gradient ◽  
Tropical Forest Dynamics ◽  
The Impact

scholarly journals Ecological responses to El Niño–induced surface fires in central Brazilian Amazonia: management implications for flammable tropical forests

2004 ◽  
Vol 359 (1443) ◽  
pp. 367-380 ◽  
Author(s):  
Jos Barlow ◽  
Carlos A. Peres
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Forest Fires ◽  
Forest Structure ◽  
El Niño ◽  
Tree Mortality ◽  
El Nino ◽  
Recovery Process ◽  
Management Implications ◽  
Brazilian Amazonia

Over the past 20 years the combined effects of El Niño–induced droughts and land–use change have dramatically increased the frequency of fire in humid tropical forests. Despite the potential for rapid ecosystem alteration and the current prevalence of wildfire disturbance, the consequences of such fires for tropical forest biodiversity remain poorly understood. We provide a pan–tropical review of the current state of knowledge of these fires, and include data from a study in a seasonally dry terra firme forest of central Brazilian Amazonia. Overall, this study supports predictions that rates of tree mortality and changes in forest structure are strongly linked to burn severity. The potential consequences for biomass loss and carbon emissions are explored. Despite the paucity of data on faunal responses to tropical forest fires, some trends are becoming apparent; for example, large canopy frugivores and understorey insectivorous birds appear to be highly sensitive to changes in forest structure and composition during the first 3 years after fires. Finally, we appraise the management implications of fires and evaluate the viability of techniques and legislation that can be used to reduce forest flammability, prevent anthropogenic ignition sources from coming into contact with flammable forests and aid the post–fire recovery process.

Impact of severe drought associated with the 1997–1998 El Niño in a tropical forest in Sarawak

2000 ◽  
Vol 16 (3) ◽  
pp. 355-367 ◽  
Author(s):  
Michiko Nakagawa ◽  
Kenta Tanaka ◽  
Tohru Nakashizuka ◽  
Tatsuhiro Ohkubo ◽  
Tsuyoshi Kato ◽  
...  
Keyword(s):  
Tropical Forest ◽  
El Niño ◽  
El Nino ◽  
Basal Area ◽  
Size Class ◽  
Severe Drought ◽  
Drought Period ◽  
Composition And Structure ◽  
Log Linear ◽  
The Impact

The impact of the unusually severe drought associated with the 1997–1998 El Niño on tropical forest dynamics in Sarawak, Malaysia was examined. Mortality during the non-drought period (1993–1997) in a core plot (1.38 ha) was 0.89 % y−1, while that during the drought period (1997–1998) in the same plot and a peripheral plot was 6.37 and 4.35 % y−1, respectively. The basal area lost in the drought interval was 3.4 times that of the annual incremental basal area in 1993–1997. Drought mortality was higher for the smaller trees, though it was less size dependent than the non-drought mortality. Dipterocarpaceae, which is the dominant family in the study plot, had a mortality 12–30 times higher in the drought than the non-drought period. There were no significant differences in mortality among the topographic types. From the results of a log-linear model (multi-factored contingency table), the death of trees was correlated with size class, indicating a change in the size-class structure of the forest. Thus, both the species composition and structure are totally affected by such an episodic drought even in a per-humid tropical forest.

scholarly journals Effects of El-Niño, Indian Ocean Dipole, and Madden-Julian Oscillation on Surface Air Temperature and Rainfall Anomalies over Southeast Asia in 2015

Atmosphere ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 352 ◽  
Author(s):  
M. Islam ◽  
Andy Chan ◽  
Matthew Ashfold ◽  
Chel Ooi ◽  
Majid Azari
Keyword(s):  
Indian Ocean ◽  
Southeast Asia ◽  
Air Temperature ◽  
El Niño ◽  
Indian Ocean Dipole ◽  
El Nino ◽  
Weather Prediction ◽  
Surface Air Temperature ◽  
Madden Julian Oscillation ◽  
Rainfall Anomalies

The Maritime Continent (MC) is positioned between the Asian and Australian summer monsoons zone. The complex topography and shallow seas around it are major challenges for the climate researchers to model and understand it. It is also the centre of the tropical warm pool of Southeast Asia (SEA) and therefore the MC gets extra attention of the researchers. The monsoon in this area is affected by inter-scale ocean-atmospheric interactions such as the El-Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Madden-Julian Oscillation (MJO). Monsoon rainfall in the MC (especially in Indonesia and Malaysia) profoundly exhibits its variability dependence on ocean-atmospheric phenomena in this region. This monsoon shift often introduces to dreadful events like biomass burning (BB) in Southeast Asia (SEA) in which some led to severe trans-boundary haze pollution events in the past. In this study, the BB episode of 2015 in the MC is highlighted and discussed. Observational satellite datasets are tested by performing simulations with the numerical weather prediction (NWP) model WRF-ARW (Weather Research and Forecast—Advanced research WRF). Observed and model datasets are compared to study the surface air temperature and precipitation (rainfall) anomalies influenced by ENSO, IOD, and MJO. Links amongst these influences have been recognised and the delayed precipitation of the regular monsoon in the MC due to their influence during the 2015 BB episode is explained and accounted for, which eventually led to the intensification of fire and a severe haze.

scholarly journals Quantifying immediate carbon emissions from El Niño-mediated wildfires in humid tropical forests

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170312 ◽  
Author(s):  
Kieran Withey ◽  
Erika Berenguer ◽  
Alessandro Ferraz Palmeira ◽  
Fernando D. B. Espírito-Santo ◽  
Gareth D. Lennox ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Carbon Emissions ◽  
El Niño ◽  
Secondary Forest ◽  
El Nino ◽  
Fire Intensity ◽  
Secondary Forests ◽  
Study Region ◽  
Fire Emissions ◽  
The Impact

Wildfires produce substantial CO 2 emissions in the humid tropics during El Niño-mediated extreme droughts, and these emissions are expected to increase in coming decades. Immediate carbon emissions from uncontrolled wildfires in human-modified tropical forests can be considerable owing to high necromass fuel loads. Yet, data on necromass combustion during wildfires are severely lacking. Here, we evaluated necromass carbon stocks before and after the 2015–2016 El Niño in Amazonian forests distributed along a gradient of prior human disturbance. We then used Landsat-derived burn scars to extrapolate regional immediate wildfire CO 2 emissions during the 2015–2016 El Niño. Before the El Niño, necromass stocks varied significantly with respect to prior disturbance and were largest in undisturbed primary forests (30.2 ± 2.1 Mg ha −1 , mean ± s.e.) and smallest in secondary forests (15.6 ± 3.0 Mg ha −1 ). However, neither prior disturbance nor our proxy of fire intensity (median char height) explained necromass losses due to wildfires. In our 6.5 million hectare (6.5 Mha) study region, almost 1 Mha of primary (disturbed and undisturbed) and 20 000 ha of secondary forest burned during the 2015–2016 El Niño. Covering less than 0.2% of Brazilian Amazonia, these wildfires resulted in expected immediate CO 2 emissions of approximately 30 Tg, three to four times greater than comparable estimates from global fire emissions databases. Uncontrolled understorey wildfires in humid tropical forests during extreme droughts are a large and poorly quantified source of CO 2 emissions. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Spatio-temporal patterns of thermal anomalies and drought over tropical forests driven by recent extreme climatic anomalies

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170300 ◽  
Author(s):  
Juan C. Jimenez ◽  
Jonathan Barichivich ◽  
Cristian Mattar ◽  
Ken Takahashi ◽  
Andrés Santamaría-Artigas ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Spatial Patterns ◽  
El Niño ◽  
El Nino ◽  
The Other ◽  
Extreme Drought ◽  
Drought Severity ◽  
Tropical Regions ◽  
Temperature Anomalies ◽  
The Impact

The recent 2015–2016 El Niño (EN) event was considered as strong as the EN in 1997–1998. Given such magnitude, it was expected to result in extreme warming and moisture anomalies in tropical areas. Here we characterize the spatial patterns of temperature anomalies and drought over tropical forests, including tropical South America (Amazonia), Africa and Asia/Indonesia during the 2015–2016 EN event. These spatial patterns of warming and drought are compared with those observed in previous strong EN events (1982–1983 and 1997–1998) and other moderate to strong EN events (e.g. 2004–2005 and 2009–2010). The link between the spatial patterns of drought and sea surface temperature anomalies in the central and eastern Pacific is also explored. We show that indeed the EN2015–2016 led to unprecedented warming compared to the other EN events over Amazonia, Africa and Indonesia, as a consequence of the background global warming trend. Anomalous accumulated extreme drought area over Amazonia was found during EN2015–2016, but this value may be closer to extreme drought area extents in the other two EN events in 1982–1983 and 1997–1998. Over Africa, datasets disagree, and it is difficult to conclude which EN event led to the highest accumulated extreme drought area. Our results show that the highest values of accumulated drought area over Africa were obtained in 2015–2016 and 1997–1998, with a long-term drying trend not observed over the other tropical regions. Over Indonesia, all datasets suggest that EN 1982–1983 and EN 1997–1998 (or even the drought of 2005) led to a higher extreme drought area than EN2015–2016. Uncertainties in precipitation datasets hinder consistent estimates of drought severity over tropical regions, and improved reanalysis products and station records are required.This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Short-term effects of drought on tropical forest do not fully predict impacts of repeated or long-term drought: gas exchange versus growth

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170311 ◽  
Author(s):  
Patrick Meir ◽  
Maurizio Mencuccini ◽  
Oliver Binks ◽  
Antonio Lola da Costa ◽  
Leandro Ferreira ◽  
...  
Keyword(s):  
Tropical Forest ◽  
El Niño ◽  
Tree Mortality ◽  
El Nino ◽  
Short Term ◽  
Sapwood Area ◽  
Plant Hydraulics ◽  
Trade Offs ◽  
The Impact

Are short-term responses by tropical rainforest to drought (e.g. during El Niño) sufficient to predict changes over the long-term, or from repeated drought? Using the world's only long-term (16-year) drought experiment in tropical forest we examine predictability from short-term measurements (1–2 years). Transpiration was maximized in droughted forest: it consumed all available throughfall throughout the 16 years of study. Leaf photosynthetic capacity was maintained, but only when averaged across tree size groups. Annual transpiration in droughted forest was less than in control, with initial reductions (at high biomass) imposed by foliar stomatal control. Tree mortality increased after year three, leading to an overall biomass loss of 40%; over the long-term, the main constraint on transpiration was thus imposed by the associated reduction in sapwood area. Altered tree mortality risk may prove predictable from soil and plant hydraulics, but additional monitoring is needed to test whether future biomass will stabilize or collapse. Allocation of assimilate differed over time: stem growth and reproductive output declined in the short-term, but following mortality-related changes in resource availability, both showed long-term resilience, with partial or full recovery. Understanding and simulation of these phenomena and related trade-offs in allocation will advance more effectively through greater use of optimization and probabilistic modelling approaches. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals History of El Niño impacts on the global carbon cycle 1957–2017: a quantification from atmospheric CO 2 data

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170303 ◽  
Author(s):  
C. Rödenbeck ◽  
S. Zaehle ◽  
R. Keeling ◽  
M. Heimann
Keyword(s):  
Carbon Cycle ◽  
Air Temperature ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Geographical Area ◽  
Geographical Location ◽  
Net Ecosystem Exchange ◽  
Mixing Ratios ◽  
The Impact

Interannual variations in the large-scale net ecosystem exchange (NEE) of CO 2 between the terrestrial biosphere and the atmosphere were estimated for 1957–2017 from sustained measurements of atmospheric CO 2 mixing ratios. As the observations are sparse in the early decades, available records were combined into a ‘quasi-homogeneous’ dataset based on similarity in their signals, to minimize spurious variations from beginning or ending data records. During El Niño events, CO 2 is anomalously released from the tropical band, and a few months later also in the northern extratropical band. This behaviour can approximately be represented by a linear relationship of the NEE anomalies and local air temperature anomalies, with sensitivity coefficients depending on geographical location and season. The apparent climate sensitivity of global total NEE against variations in pan-tropically averaged annual air temperature slowly changed over time during the 1957–2017 period, first increasing (though less strongly than in previous studies) but then decreasing again. However, only part of this change can be attributed to actual changes in local physiological or ecosystem processes, the rest probably arising from shifts in the geographical area of dominating temperature variations. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals ENSO Drives interannual variation of forest woody growth across the tropics

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170410 ◽  
Author(s):  
Sami W. Rifai ◽  
Cécile A. J. Girardin ◽  
Erika Berenguer ◽  
Jhon del Aguila-Pasquel ◽  
Cecilia A. L. Dahlsjö ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Water Deficit ◽  
Tropical Forests ◽  
El Niño ◽  
Vapour Pressure ◽  
El Nino ◽  
Vapour Pressure Deficit ◽  
Shortwave Radiation ◽  
Soil Water Deficit ◽  
Woody Growth

Meteorological extreme events such as El Niño events are expected to affect tropical forest net primary production (NPP) and woody growth, but there has been no large-scale empirical validation of this expectation. We collected a large high–temporal resolution dataset (for 1–13 years depending upon location) of more than 172 000 stem growth measurements using dendrometer bands from across 14 regions spanning Amazonia, Africa and Borneo in order to test how much month-to-month variation in stand-level woody growth of adult tree stems (NPP stem ) can be explained by seasonal variation and interannual meteorological anomalies. A key finding is that woody growth responds differently to meteorological variation between tropical forests with a dry season (where monthly rainfall is less than 100 mm), and aseasonal wet forests lacking a consistent dry season. In seasonal tropical forests, a high degree of variation in woody growth can be predicted from seasonal variation in temperature, vapour pressure deficit, in addition to anomalies of soil water deficit and shortwave radiation. The variation of aseasonal wet forest woody growth is best predicted by the anomalies of vapour pressure deficit, water deficit and shortwave radiation. In total, we predict the total live woody production of the global tropical forest biome to be 2.16 Pg C yr −1 , with an interannual range 1.96–2.26 Pg C yr −1 between 1996–2016, and with the sharpest declines during the strong El Niño events of 1997/8 and 2015/6. There is high geographical variation in hotspots of El Niño–associated impacts, with weak impacts in Africa, and strongly negative impacts in parts of Southeast Asia and extensive regions across central and eastern Amazonia. Overall, there is high correlation ( r = −0.75) between the annual anomaly of tropical forest woody growth and the annual mean of the El Niño 3.4 index, driven mainly by strong correlations with anomalies of soil water deficit, vapour pressure deficit and shortwave radiation. This article is part of the discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

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