Asian-Australian Monsoon Research Articles

Trend of Halmahera Eddy and Mindanao Eddy

Global warming, due to increasing greenhouse gases, has increased the frequency of El Niño Southern Oscillation events and influenced ocean dynamics. This research determined the trends of Mindanao Eddy’s and Halmahera Eddy’s over 28 years (1993–2020). The data used in this research consist of sea surface currents, surface wind, sea surface height, and NIŇO3.4 index. Determination of eddy currents was done using the Automated Eddies Detection method. The results showed that the Asian-Australian monsoon and El Niño Southern Oscillation events influence the characteristics of the Mindanao Eddy and Halmahera Eddy. During the Asian monsoon, the position of the Mindanao Eddy and Halmahera Eddy shifts southward, while during the Australian monsoon, it shifts northward. During El Niño, the position of the Mindanao Eddy turns eastward with a smaller diameter, but the position of the Halmahera Eddy does not shift. Conversely, during La Niña, the position of the Halmahera Eddy turns northwestward with a smaller diameter, while the position of the Mindanao Eddy remains unchanged. The shift of the Mindanao Eddy during the El Niño event is closely related to the weakening of the North Equatorial Current and the strengthening of the North Equatorial Countercurrent. On the other hand, the shift of the Halmahera Eddy during the La Niña event is related to the strengthening of the South Equatorial Current as a source of water masses for the New Guinea Coastal Current. The velocity of the Mindanao Eddy and Halmahera Eddy experienced an increasing trend in 1993-2020.

Impacts of the Asian Australian Monsoon and Indo Pacific Sea Surface Temperature on Urban Climates in Major Indonesian Cities for Low Carbon Building Design

Impacts of the Asian Australian Monsoon and Indo Pacific Sea Surface Temperature on Urban Climates in Major Indonesian Cities for Low Carbon Building Design

Asian-Australian monsoon as a mediator on North American surface air temperature anomalies

The Asian-Australian monsoon (AAM) significantly shapes global weather and climate patterns, yet existing research has primarily focused on regional monsoon subsystems rather than adopting a comprehensive global perspective on the AAM. This study addresses this gap by elucidating the interannual variability of the AAM during boreal summer and underscoring the pivotal mediating role of AAM precipitation anomalies as a driving force behind surface air temperature anomalies (SATA) over central and southern North America (CSNA). To investigate AAM characteristics, we employ an empirical orthogonal function analysis to identify the primary mode of the AAM. The corresponding principal component serves as a representative measure for the AAM. Our findings reveal a distinct ‘wet (dry) Maritime Continent-dry (wet) Western North Pacific (WNP)’ dipole pattern in strong (weak) AAM years. Vertical motion anomalies emerge as the dominant contributors to these precipitation anomalies. Both observed data and model results indicate that the sea surface temperature anomalies (SSTA) in the central and eastern Pacific (CEP) play a crucial role in explaining the vertical motion anomalies. This explanation is facilitated through two key systems: the east–west Walker circulation-like anomaly and the anomalous equatorially symmetric anticyclonic pair in the Pacific. AAM precipitation anomalies act as a mediator between SSTA in the CEP and SATA over the CSNA. These generate Rossby wave source over the WNP, triggering Rossby waves that propagate to CSNA along a great circle path. This process results in upper-level positive geopotential height anomalies, thereby influencing SATA positively over the CSNA, as illustrated by the linear baroclinic model. These findings not only deepen our understanding of the AAM but also offer novel insights into the mechanisms influencing SATA formation over North America.

Variability of the Indonesian Throughflow and Australian monsoon across the mid Pleistocene transition (IODP 363, Site U1483)

The Mid-Pleistocene Transition (MPT) between ∼1200 and ∼800 ka was associated with a major shift in global climate and was marked by a change in glacial/interglacial periodicity from ∼41 to ∼100 kyr that resulted in higher-amplitude sea-level variations and intensified glacial cooling. The sensitivity of the Indonesian Throughflow (ITF), and the Asian-Australian Monsoon dynamics to changing MPT climate remains controversial, although its understanding is important to constrain future climate projections. In this study, we analyzed radiolarian assemblages in core top samples retrieved during the RV Sonne Expedition 257 and in downcore samples from International Ocean Discovery Program (IODP) Site U1483 to estimate the variability in regional sea surface temperatures (SSTs), and to explore ITF dynamics in relation to glacio-eustatic sea-level variations and tropical monsoon strength during the MPT. Our results suggest that tropical monsoon strength and glacio-eustatic sea-level change influenced SST variations at Site U1483. Comparisons with SST data from the mid latitudes off Northwest Australia and the South China Sea suggest that SST variations at Site U1483 and in the ITF outflow into the Timor Sea are highly dependent on prevailing climate changes in the source region of the ITF, rather than on southern hemisphere. atmospheric circulation. In addition, comparisons of radiolarian abundances with X-ray fluorescence-scanning elemental data indicate that until ∼980 ka radiolarian productivity was higher during strong interglacial summer monsoons, likely because of the riverine runoff generated by monsoonal precipitation. However, at ∼980 ka pronounced winter monsoon cooling was associated with a re-organization of radiolarian production patterns in the Timor Sea.

Determination and assessment of GNSS-derived precipitable water vapor in Indonesia using Ina-CORS

This work is the first attempt to investigate the accuracy and reliability of the Ina-CORS (Indonesian Continuously Operating Reference Stations) for meteorological applications. We used the standard procedures to determine and assess the precipitable water vapor (PWV) obtained from the Global Navigation Satellite System (GNSS) measurements. The GNSS-derived zenith tropospheric delay (ZTD) was estimated using the GAMIT software, and it was then converted to PWV using surface pressure measurements and the water vapor weighted mean temperature. The results were compared against those derived from the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5) data.Comparisons against the ECMWF ERA5 data reveal the following findings. Values for the mean bias and root mean square deviation (RMSD) of the GNSS-derived ZTD over the period 2011–2020 are −6.6 mm and 14.1 mm, respectively, representing the total percentage error of about 0.4%. The total errors from the surface pressure measurements and the calculations of water vapor weighted mean temperature introduce errors to the PWV values with the magnitude less than 1 mm. The GNSS-derived PWV values over Indonesia are comparable with those derived from the ECMWF ERA5 data. The mean bias and RMSD of PWV values are −0.60 mm and 2.59 mm, respectively. In addition, spatio-temporal variations of the GNSS-derived PWV can capture the main atmospheric features that are consistent with the other results deduced from long-term rainfall data. One of the features is the annual and semiannual cycles of PWV that largely correspond to the annual migration of the Asian-Australian monsoon system. Based on these results, we can conclude that the Ina-CORS is capable enough for accurate monitoring of the Indonesian weather and climate variations.

Multi-proxy validation of glacial-interglacial rainfall variations in southwest Sulawesi

Speleothem δ18O is widely used as a proxy for rainfall amount in the tropics on glacial-interglacial to interannual scales. However, uncertainties in the interpretation of this renowned proxy pose a vexing problem in tropical paleoclimatology. Here, we present paired multi-proxy geochemical measurements for stalagmites from southwest Sulawesi, Indonesia, and confirm changes in rainfall amount across ice age terminations. Collectively, the stalagmites span two glacial-interglacial transitions from ~380,000 to 330,000 and 230,000 to 170,000 years ago. Mg/Ca in the slow-growing stalagmites is affected by water moving through the karst and prior calcite precipitation, making it a good proxy for changes in local rainfall. When paired, Mg/Ca and δ18O corroborate prominent shifts from drier glacials to wetter interglacials in the core of the Australasian monsoon domain. These shifts in rainfall occur 4,000-7,000 years later than glacial-interglacial increases in global temperature and the associated response of Sulawesi vegetation, determined by speleothem δ13C.

Evaluation of multiple gridded precipitation datasets using gauge observations over Indonesia during the Asian-Australian monsoon period

Gridded precipitation datasets are widely available from satellite observations and reanalysis model outputs. However, its performance in specific regions in the world may vary and depends on several factors, such as grid data spatial resolution, rainfall estimation algorithms, geographical location, elevation and regional climate conditions. This study aims to report on 13 gridded precipitation datasets' performance over Indonesia through direct comparisons with rain gauge measurements at various time scales over a 12-year period (2001-2012). The results show that, at daily timescales, the MERRA2 and CPC outperformed other datasets but tended to underestimate the rain gauge data in Indonesia, followed by GPCC. However, MERRA2 has smaller variation and bias than CPC. On monthly and annually timescales, CPC was found to be the best-performing dataset, followed by MERRA2, GPM-IMERG, GPCC and TRMM (TMPA), while JRA55 registered the worst performance at all timescales, followed by ERA-Interim. The performance of all datasets was better during JJA and SON than during DJF and MAM. The best performances were found in the southern (S) region of Indonesia, while the worst were in the northeast (NE) region for all months and datasets. The best performances during DJF (Asian Winter Monsoon) and JJA/SON (Australian Winter Monsoon) were found in the northwest (NW) and southern (S) regions, respectively. Most datasets overestimate the rain gauge data over Indonesia, except for GSMaP, MERRA2, CPC and CMORPH.

Dynamical Predictability of Leading Interannual Variability Modes of the Asian-Australian Monsoon in Climate Models

The dynamical prediction of the Asian-Australian monsoon (AAM) has been an important and long-standing issue in climate science. In this study, the predictability of the first two leading modes of the AAM is studied using retrospective prediction datasets from the seasonal forecasting models in four operational centers worldwide. Results show that the model predictability of the leading AAM modes is sensitive to how they are defined in different seasonal sequences, especially for the second mode. The first AAM mode, from various seasonal sequences, coincides with the El Niño phase transition in the eastern-central Pacific. The second mode, initialized from boreal summer and autumn, leads El Niño by about one year but can exist during the decay phase of El Niño when initialized from boreal winter and spring. Our findings hint that ENSO, as an early signal, is conducive to better performance of model predictions in capturing the spatiotemporal variations of the leading AAM modes. Still, the persistence barrier of ENSO in spring leads to poor forecasting skills of spatial features. The multimodel ensemble (MME) mean shows some advantage in capturing the spatiotemporal variations of the AAM modes but does not provide a significant improvement in predicting its temporal features compared to the best individual models in predicting its temporal features. The BCC_CSM1.1M shows promising skill in predicting the two AAM indices associated with two leading AAM modes. The predictability demonstrated in this study is potentially useful for AAM prediction in operational and climate services.

Monsoon Depression Amplification by Horizontal Shear and Humidity Gradients: A Shallow Water Perspective

Abstract Transient, synoptic-scale vortices produce a large fraction of total rainfall in most monsoon regions and are often associated with extreme precipitation. However, the mechanism of their amplification remains a topic of active research. For monsoon depressions, which are the most prominent synoptic-scale vortex in the Asian–Australian monsoon, recent work has suggested that meridional gradients in zonal wind in the vortex environment may produce growth through barotropic instability, while meridional gradients in environmental humidity have also been proposed to cause amplification through coupling with precipitating convection. Here, a two-dimensional shallow water model on a sphere with parameterized precipitation is used to examine the relative role played by these two environmental gradients. By systematically varying the meridional moisture gradient and meridional wind shear for both weak, quasi-linear waves and finite-amplitude isolated vortices, we show that rotational winds in the initial vortex are amplified most strongly by meridional shear of the environmental zonal wind, while vortex precipitation rates are most sensitive to environmental moisture gradients. The growth rate in the presence of both gradients is less than the sum of growth rates in the presence of isolated gradients, as the phase relation between moisture and vorticity anomalies becomes distorted with increasing shear. These results suggest that background meridional gradients in both zonal wind and environmental humidity can contribute to the amplification of vortices to monsoon depression strength, but with some degree of decoupling of the dry rotational flow and the moist convection.

Variations of Summertime SSTA Independent of ENSO in the Maritime Continent and Their Possible Impacts on Rainfall in the Asian–Australian Monsoon Region

Abstract The sea surface temperature anomalies (SSTA) in the Maritime Continent (MC) region are mainly related to local variability, ENSO, and the Indian Ocean dipole. Using the reanalysis data from NOAA and NCEP–NCAR, by employing the empirical orthogonal function (EOF) analysis, we have explored the principal mode of ENSO-independent summertime SSTA in the MC and its associations with regional climate anomalies. After ENSO signals have been removed, the leading mode of SSTA in the MC exhibits a uniformly signed pattern, which mainly varies on an interannual time scale. The maintenance mechanisms of the ENSO-independent SSTA are different in different subregions, especially over the region south of Java and the tropical northwestern Pacific. When the time coefficient of the first leading EOF mode (EOF1) is positive, warmer SSTAs are observed in the area south of Java. The oceanic dynamic heating there facilitates the warmer SSTA. Thus, the Gill-type response of the atmosphere is found over the region south of Java. The diabatic cooling in the atmosphere is dominant over the tropical northwestern Pacific where the warmer SSTA is maintained by the absorption of solar radiation due to less cloud cover there. A tilted vertical circulation is hence formed, linking the tropical southeastern Indian Ocean with the tropical northwestern Pacific. The anomalous circulations in the Asian–Australian monsoon region are affected by this ENSO-independent SSTA mode, resulting in decreased summer rainfall anomaly in the region near the southeast coast of China and increased winter precipitation anomaly over the extratropical region of Australia.

Seasonal and annual variations of the GPS-based precipitable water vapor over Sumatra, Indonesia

This study investigates the spatial distribution of seasonal and annual as well as semi-annual variations of the precipitable water vapor (PWV) over Sumatra Island, Indonesia, as revealed from a dense network of the Global Positioning System (GPS) receivers. We have analyzed the GPS-based PWV time series at 57 stations during the period of 2004 to 2020, and we revealed some features that have not yet been reported in detail by previous investigators using rainfall data. A notable feature is the presence of the seasonal PWV gradient in the northwest-southeast direction, which exist all times of the year. This gradient represents the annual migration of the Asian-Australian monsoon system, which migrates back and forth in the northwest-southeast direction. In addition, this gradient can also show the periodic changes between the wet and dry seasons over the region. The other feature is the presence of a clear demarcation line around the latitude of 2oS, separating Sumatra Island into the annual and semi-annual regimes. While the semi-annual variation tends to be concentrated in the northern side of 2oS, the annual one dominates the region in the southern side of 2oS. It is also revealed that the stations near the demarcation line are most likely to receive rainfall for most of the year.

Intraseasonal variability of global land monsoon precipitation and its recent trend

Accurate prediction of global land monsoon rainfall on a sub-seasonal (2–8 weeks) time scale has become a worldwide demand. Current forecasts of weekly-mean rainfall in most monsoon regions, however, have limited skills beyond two weeks, calling for a more profound understanding of monsoon intraseasonal variability (ISV). We show that the high-frequency (HF; 8–20 days) ISV, crucial for the Week 2 and Week 3 predictions, accounts for about 53–70% of the total (8–70 days) ISV, generally dominating the sub-seasonal predictability of various land monsoons, while the low-frequency (LF; 20–70 days)’s contribution is comparable to HF only over Australia (AU; 47%), South Asia (SA; 43%), and South America (SAM; 40%). The leading modes of HFISVs in Northern Hemisphere (NH) monsoons primarily originate from different convectively coupled equatorial waves, while from mid-latitude wave trains for Southern Hemisphere (SH) monsoons and East Asian (EA) monsoon. The Madden-Julian Oscillation (MJO) directly regulates LFISVs in Asian-Australian monsoon and affects American and African monsoons by exciting Kelvin waves and mid-latitude teleconnections. During the past four decades, the HF (LF) ISVs have considerably intensified over Asian (Asian-Australian) monsoon but weakened over American (SAM) monsoon. Sub-seasonal to seasonal (S2S) prediction models exhibit higher sub-seasonal prediction skills over AU, SA, and SAM monsoons that have larger LFISV contributions than other monsoons. These results suggest an urgent need to improve the simulation of convectively coupled equatorial waves and two-way interactions between regional monsoon ISVs and mid-latitude processes and between MJO and regional monsoons, especially under the global warming scenarios.

Monsoon Effects on Chlorophyll-a, Sea Surface Temperature, and Ekman Dynamics Variability along the Southern Coast of Lesser Sunda Islands and Its Relation to ENSO and IOD Based on Satellite Observations

The Asian–Australian Monsoon (AAM), the El Nino-Southern Oscillation (ENSO), and the Indian Ocean Dipole (IOD) have been known to induce variability in ocean surface characteristics along the southern coast of Lesser Sunda Island (LSI). However, previous studies used low spatial resolution data and little Ekman dynamics analysis. This study aims to investigate the direct influence of AAM winds on ocean surface conditions and to determine how ENSO and IOD affect the ocean surface and depth with higher spatial resolution data. In addition, the variability in Ekman dynamics is also described along with the inconsistent relationship between wind and sea surface temperature (SST) in four different areas. The results indicate that persistent southeasterly winds are likely to induce low SST and chlorophyll-a blooms. Based on the interannual variability, the positive chlorophyll-a (up to 0.5 mg m−3) and negative SST (reaching −1.5 °C) anomalies observed in the El Nino of 2015 coincide with +IOD, which also corroborates positive wind stress and Ekman Mass Transport (EMT) anomalies. In contrast, the La Nina of 2010 coincides with -IOD, and positive SST and negative chlorophyll-a anomalies (more than 1.5 °C and −0.5 mg m−3 respectively) were observed. Furthermore, we found that southern coast of Java and Bali Island have a different generated mechanism that controls SST variability.

Asian-Australian monsoon evolution over the last millennium linked to ENSO in composite stalagmite δ18O records

The Asian-Australian monsoon (AAM) system distinctly influences global climate. However, the linkage between ENSO (El Niño–Southern Oscillation) and AAM is still poorly understood over the last millennium. Here, we combined stalagmite δ18O (δ18Os) records with exceptionally high-resolution and high-precision chronologies to demonstrate a tight remote coupling between AAM and tropical ocean hydrology on the multi-year, decadal, and centennial timescales. Our results reveal that (1) There is a significant negative correlation between the multi-year weighted average precipitation δ18O (δ18Oaw) from the AAM and Southern Oscillation Index (SOI), providing a modern analogous coupling for linking stalagmite δ18O (δ18Os) and ENSO over the past 100 years. (2) Over the last millennium, the integrated δ18Os record exhibit positive excursions during the Little Ice Age (LIA), marked by a tendency for more El Niño-like state conditions in the tropical Pacific, which is consistent in SST-gradient ENSO reconstruction but different to precipitation reconstruction. (3) Wavelet and power spectrum analysis for the integrated δ18Os record in the AAM region show that there is a significant multi-year periodicity (2.2, 2.8, 3.5, 4.6 yr), conceding with the ENSO cycle (2–7 yr), whereas, some multi-decadal and centennial cycles (10.1, 17, 28.6, 52.7, 143 yr) are significant too. We provide evidence from instrumental and paleocliamte datasets (GNIP and NOAA) and propose a possible “circulation effect” mechanism responsible for variations of δ18Os in the East Asian Monsoon (EAM) and Australian Monsoon (AM) region over the last millennium.

Formation of an Intrathermocline Eddy Triggered by the Coastal‐Trapped Wave in the Northern Bay of Bengal

AbstractThe present study investigates the characteristics and mechanism of intrathermocline eddy (ITE) formation in the northern Bay of Bengal (BoB) using observations from Research Moored Array for African–Asian–Australian Monsoon Analysis and Prediction (RAMA) buoys moored at 15°N, 12°N, and 8°N along 90°E and simulations from a high‐resolution numerical model. Among the RAMA locations, a relatively large number of anticyclonic ITEs are observed in the northern parts (15°N) compared to the other two (12°N and 8°N). The observed ITEs are characterized by a double‐convex shape of isotherms in the thermocline with a vertical extent of about 100–200 m and a positive sea level anomaly in the surface. Water mass properties show that Andaman Sea (AS) water is trapped inside the core of the ITEs. Trajectories of these ITEs (especially at 15°N) suggest that most of them originated in the vicinity of Preparis Channel, the northernmost passage between BoB and AS. Our study shows that vorticity developed downstream of Preparis Channel due to the strong subsurface flow (∼100 cm/s), which carries AS water into the BoB, results in the formation of observed anticyclonic ITE in the northern BoB. Further analysis revealed that this strong subsurface flow through the Preparis Channel is caused by the propagation of downwelling coastal‐trapped waves along the boundaries of BoB, which originates from the equatorial Indian Ocean. Our study suggests that ITEs could be an important pathway of water mass distribution in the intermediate layers in this region.

Evaluation of FY-3B Reprocessed OLR Data in the Asian—Australian Monsoon Region during 2011–2019: Comparison with NOAA OLR

Evaluation of FY-3B Reprocessed OLR Data in the Asian—Australian Monsoon Region during 2011–2019: Comparison with NOAA OLR

PREFACE

The seasonal atmospheric condition over the Maritime Continent is mainly driven by the Asian-Australian Monsoon. Precipitation over the Maritime Continent is highly influenced by the intra-seasonal Madden-Julian Oscillation (MJO), also highly affected by the El-Nino Southern Oscillation (ENSO) and Indian Ocean Dipole Mode (IOD). At an interannual time scale the Maritime Continent is also crossed by Indonesia Through Flow (ITF), as the artery connecting Tropical Pacific and Indian Oceans, and acting as a crucial link of the ocean general circulation that affects not only properties of these two oceans but also global climate.This complex mixture of land and sea interaction, with various atmospheric and oceanic phenomena within, makes the Maritime Continent as a unique, enigmatic and challenging area for scientific endeavor on tropical meteorology and atmospheric sciences. Various observations and research have been coordinated, campaigned, and conducted to better understand the atmospheric and oceanic condition over the tropics, especially the Maritime Continent.Many scientific discoveries have been found to enrich the knowledge of atmospheric science on the tropics, from the International Winter Monsoon Experiment in 1978, TOGA COARE in 1993, HARIMAU that ended in 2010, to CINDY/DYNAMO in 2011. The recent Year of Maritime Continent (YMC) during 2017 - 2020 aimed to improve understanding and prediction local multi-scale variability of the Maritime Continent weather-climate system and its global impact through observations and modelling exercises, was the state-of-art for such coordinated research on the tropics. As a part of YMC program, BMKG will also be involved in Measurements and Modelling of the Indonesian Throughflow International Experiment (MINTIE) which is collaborative research among countries including Indonesia BMKG and being led by Columbia University during 2019 – 2024.LIST OF Committee, Steering Committee, Organizing Committee Leader, Leader, Secretariat & Public Relations, Treasure, Event are available in this pdf.

Relationship between cross-equatorial flows over the Bay of Bengal and Australia in boreal summer: Role of tropical diabatic heating

The interannual variability of cross-equatorial flows (CEFs) over the Asian–Australian monsoon (AAM) region during boreal summer was analyzed by applying the empirical orthogonal function (EOF) method to the meridional wind at 925 hPa. The first mode (EOF1) exhibits an in-phase relationship among different CEF channels over the AAM region, which has received much attention owing to its tight linkage with ENSO. By contrast, the second mode (EOF2) possesses an out-of-phase relationship between the Bay of Bengal (BOB) CEF (90°E) and Australian CEF, among which the New Guinea CEF near 150°E shows the most significant opposite correlation with the BOB CEF. Observational and numerical model results suggest that the equatorially asymmetric heat source (sink) over the western (eastern) Maritime Continent, closely associated with the in-situ sea surface temperature anomaly, can induce cross-equatorial northerly (southerly) flow into the heating hemisphere, which dominates the out-of-phase relationship between the BOB and New Guinea CEFs. Furthermore, an equatorially symmetric heating over the central Pacific may indirectly change the CEFs by modulating the zonal atmospheric circulation near the Maritime Continent.摘要本文通过对1979–2017年夏季925 hPa经向风异常进行经验正交函数(EOF)分解, 研究了亚澳季风区内越赤道气流的年际变化特征. 结果表明, 越赤道气流的第一模态表现为亚澳季风区内不同通道间的同相变化, 即一致加强或减弱; 第二模态表现为孟加拉湾和澳大利亚越赤道气流的反相变化, 其中新几内亚和孟加拉湾越赤道气流的反相变化最显著. 该反相模态分别对应着赤道以南地区海洋性大陆东西两侧的海温异常, 其纬向偶极型的空间分布直接导致海洋性大陆西部(东部)出现沿赤道非对称的异常热汇(热源), 它可以激发跨越赤道的南风(北风)异常, 从而有利于该反相模态的出现.

The effects of climate change on the Pleistocene rock art of Sulawesi

The equatorial tropics house some of the earliest rock art yet known, and it is weathering at an alarming rate. Here we present evidence for haloclasty (salt crystallisation) from Pleistocene-aged rock art panels at 11 sites in the Maros-Pangkep limestone karsts of southern Sulawesi. We show how quickly rock art panels have degraded in recent decades, contending that climate-catalysed salt efflorescence is responsible for increasing exfoliation of the limestone cave surfaces that house the ~ 45 to 20-thousand-year-old paintings. These artworks are located in the world’s most atmospherically dynamic region, the Australasian monsoon domain. The rising frequency and severity of El Niño-induced droughts from anthropogenic climate change (that is, higher ambient temperatures and more consecutive dry days), combined with seasonal moisture injected via monsoonal rains retained as standing water in the rice fields and aquaculture ponds of the region, increasingly provide ideal conditions for evaporation and haloclasty, accelerating rock art deterioration.

Anthropogenic influence on the intensity of extreme precipitation in the Asian‐Australian monsoon region in HadGEM3‐A‐N216

AbstractThe Asian‐Australian monsoon (AAM) region is characterized as abundant summer monsoon rainfall, which provides fresh water resources for high‐density population there. The research uses HadGEM3‐A‐N216 model simulations to compare the change of extreme rainfall intensity in the AAM region with and without anthropogenic influences. Although the anthropogenic forcing exerts a weak impact on the climatological mean distribution of the extreme precipitation, it significantly increases the extreme precipitation intensity at each degree in most parts of the AAM region, especially for the northern East Asia, the Bay of Bengal, and Australia. As the extreme degree increases from the 50–98%, the extreme precipitation intensity in the northern East Asia, the Bay of Bengal, and the Australia increase more and more rapidly, while that in the southern East Asia changes from a decreasing trend to an increasing trend. Overall, the stronger extreme precipitation is accompanied by a stronger growth trend under the anthropogenic forcing.