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)

A space domain energetics study for CO2 increasing based on SRES-A2 emission scenario

Thiswork presents a detailed investigation of the changes in the global pattern of energetics under a prescribed temporal evolution of CO2 concentration as proposed by the A2 IPCC forcing scenario (SRES-A2) using a combination of reanalysis and climate models. A validation climatology is computed using the classic Lorenz energetic formulation, with generation and dissipation components estimated as residuals.The results show a good agreement overall betweenmodels and reanalysis for the present day climate, noting that the models generally give more zonal energy and less eddy energy when compared to the reanalysis. Spatial analysis translates the above results as models depicting greater energy associated with the subtropical jet streams than effectively observed. This pattern is observed regardless of season or hemisphere. The projections for future climate scenarios suggest a further increase in the zonal kinetic energy, with a slight average reduction in all other terms. This pattern is seen in association with a substantial decrease in the conversion term mainly associated with sensible heat transport (CA) under a warmer climate. In agreement with recent work in the literature, our results suggest an overall reduction of the global energetics under increasing CO2

A Space Domain Energetics Study for CO2 Increasing Based on SRES-A2 Emission Scenario

This work presents a detailed investigation of the changes in the global pattern of energetics under a prescribed temporal evolution of CO2 concentration as proposed by the A2 IPCC forcing scenario (SRES-A2) using a combination of reanalysis and climate models. A validation climatology is computed using the classic Lorenz energetic formulation, with generation and dissipation components estimated as residuals. The results show a good agreement overall between models and reanalysis for the present day climate, noting that the models generally give more zonal energy and less eddy energy when compared to the reanalysis. Spatial analysis translates the above results as models depicting greater energy associated with the subtropical jet streams than effectively observed. This pattern is observed regardless of season or hemisphere. The projections for future climate scenarios suggest a further increase in the zonal kinetic energy, with a slight average reduction in all other terms. This pattern is seen in association with a substantial decrease in the conversion term mainly associated with sensible heat transport (CA) under a warmer climate. In agreement with recent work in the literature, our results suggest an overall reduction of the global energetics under increasing CO2

Analisis meteorologico para El Refugio de Montan J.J. Neumeyer, en San Carlos de Barilloche (Argentina), durante los inviernos de 1996-1999 y otono de 2000

EL presente trabajo muestra un resumen de los datos meteorológicos colectados en el refugio de montaña J. J. Neumeyer (41o16’S, 71o17’W, 1300 m), situado a cerca de 15 Km del centro de la ciudad turística de San Carlos de Bariloche, en Argentina, para los inviernos de 1996 al 2000. Fueron hechas observaciones de temperatura, presión, precipitación, humedad y otros elementos meteorológicos. Se compararon los datos medidos en el refugio con los datos del aeropuerto de Bariloche (41o09’S, 71o 10’W, 840 m) provistos por el Servicio Meteorológico Argentino (SMN). Los resultados indican un elevado coeficiente de correlación entre los datos de temperatura máxima en el refugio y en el aeropuerto (+0.97) y también entre los datos de presión (+0.99) en las dos localidades, con un intervalo de confianza de 99%, de acuerdo con el test T-student. La temperatura máxima promedio obtenida para el refugio quedó, en promedio, 4.4oC inferior a la temperatura máxima del aeropuerto, mientras el comportamiento de las temperaturas mínimas presentó una mayor variabilidad asociada a efectos topográficos locales. Un análisis inicial para la serie histórica de precipitación en el aeropuerto no apuntó ninguna tendencia de alteración climática en los últimos 50 años, y comparaciones con anomalías de TSM indicaron una tendencia a precipitaciones más elevadas en el periodo de invierno durante años de El Niño o cuando las aguas en la costa centro/sur de Chile se encuentran cálidas

The energy cycle associated to the Pacific Walker Circulation and its relationship to ENSO

In this paper we study the Lorenz energy cycle of the Walker circulation associated with ENSO. The robust formulation of the energetics allows drawing a clear picture of the global energy and conversion terms associated with the three dimensional domains appropriate to qualify the large scale transfers that influence, and are influenced by, the anomalies during ENSO. A clear picture has emerged in that El Niño and La Niña years have approximately opposite anomalous energy fluxes, regardless of a non-linear response identified in the potential energy fields (zonal and eddy). During El Niños the tropical atmosphere is characterized by an increase of zonal available potential energy, decrease of eddy available potential energy and decrease of kinetic energy fields. This results in weaker upper level jets and a slowing- down of the overall Walker cell. During La Niñas reversed conditions are triggered, with an acceleration of the Walker cell as observed from the positive anomalous kinetic energy. The potential energy in the Walker circulation domain during the cold phase is also reduced. An equally opposite behavior is also experienced by the energy conversion terms according to the ENSO phase. The behavior of anomalous energetics seems to be triggered at about the same time when ENSO starts to manifest for both the positive and negative phases, suggesting a coupled mechanism in which atmospheric and oceanic anomalies interact and feed back onto each other

Mean number of predicted and observed HAADs from the October-December period, averaging over randomly selected test datasets.

<p>The left half of the table shows values for the logistic regression, while the right half of the table shows values from gradient boosting. Note that the “observed” number of HAAD/non-HAAD days has a fractional component, due to the averaging over randomly partitioned testing/training sets.</p

Details of the HAADs.

<p>Abbreviations: WK = day of week, RA = raw admission numbers, NA = normalised admissions given as the number of admissions per 100,000 population, WS = wind speed at Melbourne airport at midday (units = km/h), WD = wind direction (i.e. from which the wind is blowing) at Melbourne airport at midday (units = degrees clockwise from North), EW = east-west component of the wind-speed at Melbourne airport at midday (units = km/h, positive means winds from the west), NS = north-south component of the wind-speed at Melbourne airport at midday (units = km/h, positive means winds from the south), PR = precipitation at Melbourne airport from 00:00h to 23:59h (units = mm), TM = temperature at Melbourne airport at midday (units = ° C), RH = relative humidity at Melbourne airport at midday (units = %), TS = thunderstorm reported at Melbourne airport from 00:00h to 23:59h (Y = yes, N = no), GR = daily grass pollen concentration at the University of Melbourne averaged from 16:00h the previous day to 16:00h the date stated (units = grains/m³), NG = daily non-grass pollen concentration, <i>x</i>_lg = “lagged” average value of variable <i>x</i> over the 3 days prior to the given day (i.e. not including the value on the given day), O₃ = daily average ozone (units = parts per billion by volume), PM_2.5 = daily average particulate matter with an aerodynamic diameter less than 2.5 <i>μ</i> m (units = <i>μ</i> g/m³), NA = not available.</p