Tropical cyclone contribution to extreme rainfall over southwest Pacific Island nations

Southwest Pacific nations are among some of the worst impacted and most vulnerable globally in terms of tropical cyclone (TC)-induced flooding and accompanying risks. This study objectively quantifies the fractional contribution of TCs to extreme rainfall (hereafter, TC contributions) in the context of climate variability and change. We show that TC contributions to extreme rainfall are substantially enhanced during active phases of the Madden–Julian Oscillation and by El Niño conditions (particularly over the eastern southwest Pacific region); this enhancement is primarily attributed to increased TC activity during these event periods. There are also indications of increasing intensities of TC-induced extreme rainfall events over the past few decades. A key part of this work involves development of sophisticated Bayesian regression models for individual island nations in order to better understand the synergistic relationships between TC-induced extreme rainfall and combinations of various climatic drivers that modulate the relationship. Such models are found to be very useful for not only assessing probabilities of TC- and non-TC induced extreme rainfall events but also evaluating probabilities of extreme rainfall for cases with different underlying climatic conditions. For example, TC-induced extreme rainfall probability over Samoa can vary from ~ 95 to ~ 75% during a La Niña period, if it coincides with an active or inactive phase of the MJO, and can be reduced to ~ 30% during a combination of El Niño period and inactive phase of the MJO. Several other such cases have been assessed for different island nations, providing information that have potentially important implications for planning and preparing for TC risks in vulnerable Pacific Island nations. © 2021, The Author(s). *Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Anil Deo and Savin Chand” is provided in this record*

The varied impacts of El Nino-Southern Oscillation on Pacific Island climates

El Nino-Southern Oscillation (ENSO) drives interannual climate variability in many tropical Pacific island countries, but different El Nino events might be expected to produce varying rainfall impacts. To investigate these possible variations, El Nino events were divided into three categories based on where the largest September-February sea surface temperature (SST) anomalies occur: warm pool El Nino (WPE), cold tongue El Nino (CTE), and mixed El Nino (ME), between the other two. Large-scale SST and wind patterns for each type of El Niño show distinct and significant differences, as well as shifts in rainfall patterns in the main convergence zones. As a result, November to April rainfall in many Pacific island countries is significantly different among the El Nino types. In western equatorial Pacific islands, CTE events are associated with drier than normal conditions whereas ME and WPE events are associated with significantly wetter than normal conditions. This is due to the South Pacific convergence zone and intertropical convergence zone moving equatorward and merging in CTE events. Rainfall in the convergence zones is enhanced during ME and WPE and the displacement is smaller. La Nina events also show robust impacts that most closely mirror those of ME events. In the northwest and southwest Pacific strong CTE events have much larger impacts on rainfall than ME and WPE, as SST anomalies and correspondingly large-scale surface wind and rainfall changes are largest in CTE. While variations in rainfall exist between different types of El Nino and the significant impacts on Pacific countries of each event are different, the two extreme CTE events have produced the most atypical impacts

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

State of the climate in 2018

In 2018, the dominant greenhouse gases released into Earth’s atmosphere—carbon dioxide, methane, and nitrous oxide—continued their increase. The annual global average carbon dioxide concentration at Earth’s surface was 407.4 ± 0.1 ppm, the highest in the modern instrumental record and in ice core records dating back 800 000 years. Combined, greenhouse gases and several halogenated gases contribute just over 3 W m−2 to radiative forcing and represent a nearly 43% increase since 1990. Carbon dioxide is responsible for about 65% of this radiative forcing. With a weak La Niña in early 2018 transitioning to a weak El Niño by the year’s end, the global surface (land and ocean) temperature was the fourth highest on record, with only 2015 through 2017 being warmer. Several European countries reported record high annual temperatures. There were also more high, and fewer low, temperature extremes than in nearly all of the 68-year extremes record. Madagascar recorded a record daily temperature of 40.5°C in Morondava in March, while South Korea set its record high of 41.0°C in August in Hongcheon. Nawabshah, Pakistan, recorded its highest temperature of 50.2°C, which may be a new daily world record for April. Globally, the annual lower troposphere temperature was third to seventh highest, depending on the dataset analyzed. The lower stratospheric temperature was approximately fifth lowest. The 2018 Arctic land surface temperature was 1.2°C above the 1981–2010 average, tying for third highest in the 118-year record, following 2016 and 2017. June’s Arctic snow cover extent was almost half of what it was 35 years ago. Across Greenland, however, regional summer temperatures were generally below or near average. Additionally, a satellite survey of 47 glaciers in Greenland indicated a net increase in area for the first time since records began in 1999. Increasing permafrost temperatures were reported at most observation sites in the Arctic, with the overall increase of 0.1°–0.2°C between 2017 and 2018 being comparable to the highest rate of warming ever observed in the region. On 17 March, Arctic sea ice extent marked the second smallest annual maximum in the 38-year record, larger than only 2017. The minimum extent in 2018 was reached on 19 September and again on 23 September, tying 2008 and 2010 for the sixth lowest extent on record. The 23 September date tied 1997 as the latest sea ice minimum date on record. First-year ice now dominates the ice cover, comprising 77% of the March 2018 ice pack compared to 55% during the 1980s. Because thinner, younger ice is more vulnerable to melting out in summer, this shift in sea ice age has contributed to the decreasing trend in minimum ice extent. Regionally, Bering Sea ice extent was at record lows for almost the entire 2017/18 ice season. For the Antarctic continent as a whole, 2018 was warmer than average. On the highest points of the Antarctic Plateau, the automatic weather station Relay (74°S) broke or tied six monthly temperature records throughout the year, with August breaking its record by nearly 8°C. However, cool conditions in the western Bellingshausen Sea and Amundsen Sea sector contributed to a low melt season overall for 2017/18. High SSTs contributed to low summer sea ice extent in the Ross and Weddell Seas in 2018, underpinning the second lowest Antarctic summer minimum sea ice extent on record. Despite conducive conditions for its formation, the ozone hole at its maximum extent in September was near the 2000–18 mean, likely due to an ongoing slow decline in stratospheric chlorine monoxide concentration. Across the oceans, globally averaged SST decreased slightly since the record El Niño year of 2016 but was still far above the climatological mean. On average, SST is increasing at a rate of 0.10° ± 0.01°C decade−1 since 1950. The warming appeared largest in the tropical Indian Ocean and smallest in the North Pacific. The deeper ocean continues to warm year after year. For the seventh consecutive year, global annual mean sea level became the highest in the 26-year record, rising to 81 mm above the 1993 average. As anticipated in a warming climate, the hydrological cycle over the ocean is accelerating: dry regions are becoming drier and wet regions rainier. Closer to the equator, 95 named tropical storms were observed during 2018, well above the 1981–2010 average of 82. Eleven tropical cyclones reached Saffir–Simpson scale Category 5 intensity. North Atlantic Major Hurricane Michael’s landfall intensity of 140 kt was the fourth strongest for any continental U.S. hurricane landfall in the 168-year record. Michael caused more than 30 fatalities and $25 billion (U.S. dollars) in damages. In the western North Pacific, Super Typhoon Mangkhut led to 160 fatalities and$6 billion (U.S. dollars) in damages across the Philippines, Hong Kong, Macau, mainland China, Guam, and the Northern Mariana Islands. Tropical Storm Son-Tinh was responsible for 170 fatalities in Vietnam and Laos. Nearly all the islands of Micronesia experienced at least moderate impacts from various tropical cyclones. Across land, many areas around the globe received copious precipitation, notable at different time scales. Rodrigues and Réunion Island near southern Africa each reported their third wettest year on record. In Hawaii, 1262 mm precipitation at Waipā Gardens (Kauai) on 14–15 April set a new U.S. record for 24-h precipitation. In Brazil, the city of Belo Horizonte received nearly 75 mm of rain in just 20 minutes, nearly half its monthly average. Globally, fire activity during 2018 was the lowest since the start of the record in 1997, with a combined burned area of about 500 million hectares. This reinforced the long-term downward trend in fire emissions driven by changes in land use in frequently burning savannas. However, wildfires burned 3.5 million hectares across the United States, well above the 2000–10 average of 2.7 million hectares. Combined, U.S. wildfire damages for the 2017 and 2018 wildfire seasons exceeded $40 billion (U.S. dollars)

Unambiguous warming in the western tropical Pacific primarily caused by anthropogenic forcing

Small Island Developing States in the tropical western Pacific are among the most vulnerable to climate change. While a great deal of information on the observed climate change trends and their cause is available for many other regions and for the globe as a whole, much less information has been available specifically for the Pacific. Here, we show that warming over the past 50years in the western Pacific is evident in recently homogenized tropical station data, and in gridded surface temperature data sets for the region. The warming has already emerged from the background climate variability. The observational data and Coupled Model Intercomparison Project Phase 5 climate model output are used to show that the observed warming was primarily caused by human-forced changes to the earth's radiative balance. Further warming is projected to occur in the same models under all three Representative Concentration Pathways (RCPs) considered (RCP2.6, RCP4.5 and RCP8.5), with the magnitude far exceeding the warming to date under the two scenarios with higher emissions (RCP4.5 and RCP8.5)

A new index for variations in the position of the South Pacific convergence zone 1910/11-2011/2012

Quality controlled and recently homogenised mean sea level pressure records for the South Pacific are used to specify the location and variability of the South Pacific convergence zone (SPCZ) during the austral warm season (November-April). The SPCZ is the world's largest rainfall band during the austral summer, when it dominates the climate of the South Pacific. A new index called the South Pacific convergence zone index (SPCZI) is derived, and is shown to be coherent with changes in low level wind convergence associated with the SPCZ. This index replaces the earlier SPCZ position index because it uses higher quality mean sea level pressure data than the superseded index and extends the time series further forward in time. The SPCZI allows interannual to decadal variability in the climate of the South Pacific to be tracked for more than a century from 1910/1911 to 2011/2012. During El Niño episodes the SPCZ is displaced by about 1°-3° east, and La Niña events 1°-3° west of the mean position on average. The index indicates a striking movement eastward for the period 1977/78-1998/99, compared with 1944/45-1976/77 in association with the Interdecadal Pacific oscillation (IPO). The eastward movement of the SPCZ in the late twentieth century is related to significant precipitation trends in the South Pacific region. Since 1998/99 the SPCZ has regressed westward with the negative phase change of the IPO. The long-term trend in the SPCZI is very small relative to the interannual to decadal variability and is not statistically significant, suggesting that there has been little overall change in the mean position of the SPCZ over the past century. © 2014 Springer-Verlag Berlin Heidelberg

Observed and projected changes in surface climate of tropical Pacific Islands

Climate for a particular location and time of year is a description of the typical weather conditions experienced over a representative period of time (generally a few decades). Importantly, climate also describes the typical year-to-year variations and weather extremes of a region. The natural and managed biological systems on which we rely have become attuned to these local prevailing climate conditions. Earth’s climate varies naturally over a wide range of timescales. It varies from year to year and decade to decade due to a range of factors that can be either internal (such as the El Niño-Southern Oscillation and the Pacific Decadal Oscillation) or external (such as the amount of incoming solar radiation, or volcanic aerosols) to the climate system (Bindoff et al. 2013; Hartmann et al. 2013). Over much longer timescales, changes in the Earth’s position relative to the Sun have produced swings between glacial and interglacial conditions (Masson-Delmotte et al. 2013). However, since the start of the Industrial Revolution in the late 18th century we have entered a new era of rapid global climate change that, while still influenced by natural cycles and forcings, is primarily driven by human actions. This is anthropogenic climate change (Stocker et al. 2013)

Climate Change in the Pacific 2022: Historical and Recent Variability, Extremes and Change

<p>This report presents key scientific findings from the second phase of the Climate and Oceans Support Program in the Pacific (COSPPac, July 2018–June 2023), Seasonal Prediction and the Pacific Sea Level and Geodetic Monitoring (PSLGM) projects. The report contributes to COSPPac's aim for Pacific Island national meteorological services to understand and use climate, ocean and sea level data and information to develop and disseminate useful products and services to Pacific Island governments and communities, building resilience against the impact of climate change, climate variability and disasters. </p><p>The report also provides an update of scientific understanding of large-scale climate processes, variability and extremes in the western tropical Pacific first presented in the Pacific Climate Change Science Program (PCCSP) Climate Change in the Pacific: Scientific Assessment and New Research, Volume 2, Country Reports (2011) and the Pacific–Australia Climate Change Science and Adaptation Planning (PACCSAP) Program Climate Variability, Extremes and Change in the Western Tropical Pacific: New Science and Updated Country Reports (2014).</p><p>The work is designed to complement the recently released 'NextGen' Projections for the Western Tropical Pacific country reports and provide finer-scale partner country historical climate change information not presented in the Intergovernmental Panel on Climate Change (IPCC)'s Sixth Assessment Report (AR6), Climate Change 2021: The Physical Science Basis, and World Meteorological Organization (WMO) Regional Association Five (RA-V) Pacific Regional Climate Centre (RCC) Network's Pacific Climate Change Monitor (PCCM) Report (2022).</p&gt

Climate Change in the Pacific 2022: Historical and Recent Variability, Extremes and Change

<p>This report presents key scientific findings from the second phase of the Climate and Oceans Support Program in the Pacific (COSPPac, July 2018–June 2023), Seasonal Prediction and the Pacific Sea Level and Geodetic Monitoring (PSLGM) projects. The report contributes to COSPPac's aim for Pacific Island national meteorological services to understand and use climate, ocean and sea level data and information to develop and disseminate useful products and services to Pacific Island governments and communities, building resilience against the impact of climate change, climate variability and disasters. </p><p>The report also provides an update of scientific understanding of large-scale climate processes, variability and extremes in the western tropical Pacific first presented in the Pacific Climate Change Science Program (PCCSP) Climate Change in the Pacific: Scientific Assessment and New Research, Volume 2, Country Reports (2011) and the Pacific–Australia Climate Change Science and Adaptation Planning (PACCSAP) Program Climate Variability, Extremes and Change in the Western Tropical Pacific: New Science and Updated Country Reports (2014).</p><p>The work is designed to complement the recently released 'NextGen' Projections for the Western Tropical Pacific country reports and provide finer-scale partner country historical climate change information not presented in the Intergovernmental Panel on Climate Change (IPCC)'s Sixth Assessment Report (AR6), Climate Change 2021: The Physical Science Basis, and World Meteorological Organization (WMO) Regional Association Five (RA-V) Pacific Regional Climate Centre (RCC) Network's Pacific Climate Change Monitor (PCCM) Report (2022).</p&gt

Protocol: Using N-of-1 tests to identify responders to melatonin for sleep disturbance in Parkinson's disease

Background 40% of Parkinson's Disease (PD) sufferers experience insomnia, impacting health and quality of life for patients and family members, especially carers. There is little evidence that current treatments are effective. Objectives To determine the effectiveness of melatonin in reducing insomnia in 44 individuals with PD using N-of-1 trials. To aggregate group data to arrive at population estimates of effectiveness (measured by improvements in PDSS-2) and safety (measured by adverse events) of melatonin in improving insomnia in PD. To assess the feasibility of offering N-of-1 trials for insomnia in PD. Methodology Participants will receive either immediate-release melatonin or placebo in random order in 3 paired two-week treatment periods (12 weeks total). Based on their response in a two-week run-in period on 3 mg daily, they will trial either 3 mg or 6 mg. Patients will keep daily sleep diaries and wear a MotionWatch throughout. After the trial patients will discuss their individual report with their doctor, which provides direct feedback about effectiveness and safety of melatonin for them. Statistical methods We will analyse N-of-1 tests 1) individually: effects of melatonin on PDSS-2 and safety will be reported; and 2) aggregated across individual N-of-1 studies, combined using a Bayesian multilevel random effects model, which will account for repeated measures on individuals over time, and will return posterior estimates of overall treatment effect, and effect in each individual. Clinical Trial Registration number ACTRN12617001103358