Mario Rohrer

Meteodat GmbH | METEODAT · climatology

The rainy season is of high importance for livelihoods in the Southern Peruvian Andes (SPA), especially for agriculture, which is mainly rain fed and one of the main income sources in the region. Therefore, knowledge and predictions of the rainy season such as its onset and ending are crucial for planning purposes. However, such information is curr...

Air Pollution is preferentially accumulating beneath a thermal inversion often characterized by mist, fog, haze or smog. Peaks of fine particulate matter (PM2.5) are often measured during such conditions. These peaks may modulate the Spreading & Virulence of Covid-19.

Heavy precipitation episodes are particularly hazardous in mid-sized alpine catchments where runoff tends to increase rapidly after strong rainfall, leaving limited time for warning. A high-quality, unbiased forecast of heavy precipitation with long enough lead times (2–5 days) and an adequate spatial resolution is thus crucial for decision makers....

Climate change and related impacts over the Indian Himalayan Region (IHR) remains poorly quantified. The present study reviews observed and modelled changes in the climate, cryosphere and impacts related to hazards, agriculture and ecosystems. An increasing temperature trend over the IHR is reported, which over a few locations is found to be higher...

A probe of a patient, seeking help in an emergency ward of a French hospital in late December 2019 because of Influenza like symptoms, was retrospectively tested positive to COVID-19. Despite the early appearance of the virus in Europe, the prevalence and virulence appeared to be low for several weeks, before the spread and severity of symptoms inc...

The development and dissemination of weather and climate information is crucial to improve people’s resilience and adaptability to climate variability and change. The impacts of climate variability and change are generally stronger for disadvantaged population groups due to their limited adaptive and coping capacities. For instance, smallholder fa...

A probe of a patient, seeking help in an emergency ward of a French hospital in late December 2019 because of Influenza like symptoms, was retrospectively tested positive to COVID-19. Despite the early appearance of the virus in Europe, the prevalence and virulence appeared tobe low for several weeks, before the spread and severity of symptoms incr...

The intensity and phase of precipitation at the ground surface can have important implications not only for meteorological and hydrological situations but also in terms of hazards and risks. In the field, Thies disdrometers are sometimes used to monitor the quantity and nature of precipitation with high temporal resolution and very low maintenance...

Die Kombination von Flüssigniederschlag und Schneeschmelze in voralpinen und alpinen Gebieten hat bereits in der Vergangenheit zu schwerwiegenden Überschwemmungen geführt. Im Zuge des Klimawandels muss gerade in voralpinen Gebieten mit einer Zunahme solcher Ereignisse gerechnet werden. Um die Bereitschaft der Behörden und der Bevölkerung im Ereigni...

In the southern Peruvian Andes communities are highly dependent on climatic conditions due to the mainly rain‐fed agriculture and the importance of glaciers and snow melt as a freshwater resource. Longer‐term trends and year‐to‐year variability of precipitation or temperature severely affect living conditions. This study evaluates seasonal precipit...

Abstract. The intensity and phase of precipitation at the ground surface can have important implications for meteorological and hydrological situations, but also in terms of hazards and risks. In the field, Thies disdrometers are sometimes used to monitor the quantity and nature of precipitation with high temporal resolution and very low maintenanc...

Los posibles cambios en el comportamiento de la temperatura y precipitación para 2016-2045, relativos al período 1971-2000, en las localidades de Urubamba y granja Kcayra, ubicadas en Cusco, Andes centrales de Sudamérica, se han estimado mediante la técnica multivariada de Componentes Principales y sus Funciones Ortogonales Empíricas asociadas. Los...

The Bernese Alps are a region that is very prone for the initiation of thunderstorms. In fact, the flow and convergence of air and water vapor from the Swiss Plateau to the Swiss Alps is frequently favouring the formation of isolated rainfall events, which then may cause loss and damage in settlements. Due to the complex topography of the Bernese A...

Präzise Schneemessungen sind auch im Zeitalter der Satellitentechnik und des Ein- satzes von Fernerkundungsmethoden eine grosse Herausforderung. Für die Abschät- zung der Schneedeckenverteilung stellen dabei moderne Hilfsmittel, wie beispiels- weise der Einsatz von Drohnen, die mit digitalen Kameras bestückt sind, eine wertvolle Hilfe dar. Die phot...

Präzise Schneemessungen sind auch im Zeitalter der Satellitentechnik und des Ein- satzes von Fernerkundungsmethoden eine grosse Herausforderung. Für die Abschät- zung der Schneedeckenverteilung stellen dabei moderne Hilfsmittel, wie beispiels- weise der Einsatz von Drohnen, die mit digitalen Kameras bestückt sind, eine wertvolle Hilfe dar. Die phot...

Rain‐on‐snow (RoS) events have caused severe floods in mountainous catchments in the recent past. Challenges in forecasting such events are uncertainties in meteorological input variables, the accurate estimation of snow cover and deficits in process understanding during runoff formation. Here, we evaluate the potential of the European Centre for M...

The extent of the Hadley cell is widening since about 1980 in both hemispheres. This means that the dry zones - characterized by the sinking air masses of the Hadley cell - are expanding poleward. When taking precipitation minus evaporation (P-E) as an index, CMIP5 models are consistently projecting a further bulging of this dry zone, currently ext...

Remarkably heavy and devastating rainfalls affected large parts of Peru during the austral summer 2016–2017. These rainfalls favoured widespread land sliding and extensive flooding and generated one of the most severe disasters of Peru since the 1997–1998 El Niño event. The amount of rainfall recorded between January and March 2017 only compares to...

Extreme precipitation events with high local precipitation intensities, heavy snowfall or extensive freezing rain can have devastating impacts on society and economy. Not only is the quantitative forecast of such events sometimes difficult and associated with large uncertainties, also are the potential consequences highly complex and challenging to...

Impact forecasts of extreme events are inherently uncertain; all the more this is the case for the estimation of those impacts based on climate scenarios for the next decades. There are at least three sources of uncertainty: (I) the imperfection of the climate models, (II) the uncertainty in estimating the impacts and (III) the future emission path...

In this study, we analyze the linkage between atmosphere and ocean modes and winter flood variability over the 20th century based on long-term flow-discharge series, historical archives, and tree-ring records of past floods in the North Atlantic Basin (NAB). The most extreme winter floods occurred in 1936 and had strong impacts on either side of th...

Supplementary Information: On the extraordinary winter flood episode over the North Atlantic Basin in 1936

The snowfall limit has important implications for different hazardous processes associated with prolonged or heavy precipitation such as flash floods, rain-on-snow events and freezing precipitation. To increase preparedness and to reduce risk in such situations, early warning systems are frequently used to monitor and predict precipitation events at d...

The occurrence of El Niño has been generally considered the main driver of hydro‐geomorphic processes in Peru. However, the climatic characterization of hydro‐geomorphic events (HGE) occurring in the absence of El Niño remains scarce. Information contained in the DesInventar disaster database suggests a widespread occurrence of HGE associated to co...

Abstract Purpose – Although the importance of climate change is generally acknowledged, its impacts are often not taken into account explicitly when planning development projects. This being due to limited resources, among others, this paper aims to propose a simple and low-cost approach to assess the viability of human activities under climate cha...

Along with air temperatures, the freezing level height (FLH) has risen over the last decades. The mass balance of tropical glaciers in Peru is highly sensitive to a rise in the FLH, mainly due to a decrease in accumulation and increase of energy for ablation caused by reduced albedo. Knowledge of future changes in the FLH is thus crucial to estimat...

In situ climatological observations are essential for studies related to climate trends and extreme events. However, in many regions of the globe, observational records are affected by a large number of data quality issues. Assessing and controlling the quality of such datasets is an important, often overlooked aspect of climate research. Besides a...

Water from glaciers is crucial for the Peruvian hydropower production. Hence, we investigate the glacier-atmosphere and climate interactions in the Cordillera Vilcanota, considering scenarios of significant precipitation reductions until 2100. The glacier mass balance model ITGG-2.0 is used for analysing the energy balance components regarding the...

Within the context of the Climate Change Adaptation Program (PACC), a number of scientific investigations on water resources, natural disasters and perceptions by local people highlight adaptation needs in the regions of Cusco and Apurímac in Peru, considering past, present-day and future climate conditions. This chapter compiles their findings and...

CLIMANDES is a pilot twinning project between the National Weather Services of Peru and Switzerland (SENAMHI and MeteoSwiss), developed within the Global Framework for Climate Services of the World Meteorological Organization (WMO). Split in two modules, CLIMANDES aims at improving education in meteorology and climatology in support of the WMO Regi...

In Peru several hydropower companies produce energy in glaciated catchments located in the Cordilleras Blanca (Santa river), Vilcanota (Vilcanota-Urubamba river) and Central (Cañete river). In this context, our study investigates the glacier atmosphere and climate change interactions considering furthermore a scenario of significant precipitation r...

Knowing the height of the snowfall limit during precipitation events is crucial for better understanding a number of hydro-climatic processes, for instance glacier-climate interactions or runoff from high mountain catchments. However, knowledge on heights of the phase change during precipitation events is limited by the small number of meteorologic...

Despite the important role of supraglacial debris in ablation, knowledge of debris thickness on Himalayan glaciers is sparse. A recently developed method based on reanalysis data and thermal band satellite imagery has proved to be potentially suitable for debris thickness estimation without the need for detailed field data. In this study, we furthe...

Projected future trends in water availability are associated with large uncertainties in many regions of the globe. In mountain areas with complex topography, climate models have often limited capabilities to adequately simulate the precipitation variability on small spatial scales. Also, their validation is hampered by typically very low station d...

This edited volume, showcasing cutting-edge research, addresses two primary questions - what are the main drivers of change in high-mountains and what are the risks implied by these changes? From a physical perspective, it examines the complex interplay between climate and the high-mountain cryosphere, with further chapters covering tectonics, volc...

Damage caused by weather- and climate-related disasters have increased over the past decades, and growing exposure and wealth have been identified as main drivers of this increase. Disaster databases are a primary tool for the analysis of disaster characteristics and trends at global or national scales, and they support disaster risk reduction and...

En el Perú se ubican cerca del 71% de los glaciares tropicales del planeta, y los glaciares de la Cordillera Blanca (norte de Lima) son los más estudiados; del resto de los glaciares se tiene un limitado conocimiento basado en la información que proporcionan las imágenes de satélite. Ante esta situación el Proyecto de Adaptación al Retroceso Aceler...

Despite the fact that the fast-growing population of Central Asia strongly depends on glacial melt water for fresh water supply, irrigation and hydropower production, the impact of glacier shrinkage on water availability remains poorly understood. With an annual area loss of 0.36 to 0.76%, glaciers are retreating particularly fast in the northern T...

Loss and damage caused by weather and climate related disasters have increased over the past decades, and growing exposure and wealth have been identified as main drivers of this increase. Disaster databases are a primary tool for the analysis of disaster characteristics and trends at global or national scales, and support disaster risk reduction a...

The tropical Andes have been recognized as one of the most vulnerable regions to climate change. Recent research shows that climatic changes in the region are not uniform. However, in many sites, critical information on observed trends are missing and unclear, representing barriers to design and implement appropriate climate change adaptation measu...

In high-mountain areas climatic extreme events can combine with effects of gradual climate change to form cascading processes, occasionally resulting in major disasters. Heavy precipitation events thereby evolve into mass movement processes such as landslides, avalanches and debris flows that can devastate urban areas at the foot of mountains. The...

The Andes of Peru are among the regions most severely affected by glacier and high-mountain hazards over the past 100 years. Large-scale disasters with thousands of people killed are on record, including ice/rock avalanches, debris flows, and glacier lake outburst floods (GLOF's). Effects of climate change such as glacier retreat and formation of g...

The Cordillera Vilcanota in the Southern Peruvian Andes is the second largest ice-covered Cordillera in Peru (after the Cordillera Blanca) and serves for the Cusco Region as a temporary water storage for fresh-water and hydropower generation and irrigation. Despite the Cordillera Vilcanota's size and socio-economic relevance, there has so far no co...

El presente documento es resultado del proyecto AndesPlus, que fue ejecutado en el marco del Proyecto de Adaptación al Impacto del Retroceso acelerado de Glaciares en los Andes Tropicales (PRAA) que se implementa en los países de la región andina contando con el Banco Mundial como agencia de implementación y la Secretaría General de la Comunidad An...

The role of glaciers as temporal water reservoirs is particularly pronounced in the (outer) tropics because of the very distinct wet/dry seasons. Rapid glacier retreat caused by climatic changes is thus a major concern, and decision makers demand urgently for regional/local glacier evolution trends, ice mass estimates and runoff assessments. Howeve...

Recent scientific assessment studies of climate change impacts, including those from the Intergovernmental Panel on Climate Change, provide evidence of the negative effects of climate variability and change on natural and human systems. For instance, recent climate trends have caused loss in wheat and maize production, negatively affected coral ree...

Multi-type hydrometeorological hazards such as landslides, debris flows and floods are recurring all over the Andes region and cause death to local people and widespread damage to population centers and infrastructure. Such disastrous events are also a threat to development because they often destroy livelihood conditions of the most poor and vulne...

The Cusco and Apurímac region (Southern Peru) in the outer tropical Andes is characterized by a distinct wet and dry season. The climatology of the Andes region in southern Peru is complex and mainly influenced by tropical and extra tropical upper level-large scale circulation as well as by local convection. For the past decades, observations from...

The role of glaciers as temporal water reservoirs is particularly pronounced in the (outer) tropics because of the very distinct wet-dry seasons. Rapid glacier retreat caused by climatic changes is thus a major concern and decision makers demand urgently for regional/local glacier evolution trends, ice mass estimates and runoff assessments. However...

In the frame of a Swiss-Peruvian climate change adaptation initiative (PACC), operational and historical data series of more than 100 stations of the Peruvian Meteorological and Hydrological Service (SENAMHI) are now accessible in a dedicated data portal. The data portal allows for example the comparison of data series or the interpolation of spati...

Climate time series are of major importance for base line studies for climate change impact and adaptation projects. However, in mountain regions and in developing countries there exist significant gaps in ground based climate records in space and time. Specifically, in the Peruvian Andes spatially and temporally coherent precipitation information...

Climate time series are of major importance for base line studies for climate change impact and adaptation projects. However, in mountain regions and in developing countries there exist significant gaps in ground based climate records in space and time. Specifically, in the Peruvian Andes spatially and temporally coherent precipitation information...

As a basis of a joint Swiss-Peruvian effort focused on water resources, food security and disaster preparedness (Peruvian Climate Adaptation Project, PACC) clean and homogenized meteorological datasets have been elaborated for the Cusco and Apurimac Regions in the Central Andes. Operational and historical data series of more than 100 stations of th...

The so-called reference evapotranspiration (ETo) is one of the key variables for the assessment of crop water requirements and irrigation needs. Standard methods are available for computing ETo as well as for the pre-processing of the meteorological data. Many of them have been developed and tested with respect to stations situated at low altitudes...

Poster presented at the Meeting of the Americas of the American Geophysical Union The Cusco and Apurimac regions in the Central Andes of Peru are characterized by distinct wet and dry seasons and are highly vulnerable to annual and inter-annual precipitation variability. This study aims at advancing knowledge on monthly wet-season precipitation pat...