Statistical and graphical depiction of climate
With adequate measurements of the climatic conditions covering many years, it is possible to define what is considered normal and what is an extreme event for any part of the world. Data gathered over the 30-year period from 1961 to 1990 define the latest Normals used for climate reference. At any given time of the year, an extreme high temperature might be defined as one that occurs only once in every 30 years. A cold winter or hot summer can be specified in a similar way, or in terms of the number of days below or above defined exceptional values. This means that when there is a succession of extremes, or more extreme events over a period (e.g. season), it is possible to estimate whether they seem to be part of the normal expectation for the locality, or are so unlikely that they can only be explained in terms of some more radical shift in the climate. The basic properties of any data
series, for example temperature, can be defined in terms of the mean over time and the amount of variance about the mean.
Other meteorological variables exhibit more complicated statistical properties. For instance,
rainfall is episodic. In many parts of the world, much of the annual rainfall falls in a short rainy season. In addition, most of that rain may be concentrated in a few heavy falls and small shifts in the large-scale weather patterns from year to year may significantly alter the amount and distribution of seasonal rainfall. More complex techniques usually are needed to interpret variations in rainfall.
Trusting climate statistics
Handling the statistics of rare events is of particular importance because we are so vulnerable to extreme weather. There is, for example, a special need to have reliable measurements over as long a time as possible, in order to build up a reliable set of statistics for what are inherently rare events. One complicating factor can arise from changes at the site where the measurements were made and in the instruments used. One well-known site problem results from the expansion of urban areas around an observatory. Urbanization changes many characteristics of the local climate, notably the replacement of cooling trees with concrete and asphalt that heat up during the day but cool only slowly at night.
Buildings and structures also change the ground-level wind flow and create eddies. Urbanization can also lead to rapid rainfall runoff and increases in flash flooding. In rural areas the smaller shifts that may occur are more difficult to detect. For instance, the growth of trees around a farmstead that maintains a weather station alters the local wind flow and temperature patterns, and so reduces extreme wind speeds and the incidence of frosts (where they occur). The trend in the observations reflects the change of the microclimate of the farmstead but the general climate may not have changed. Greater challenges arise when it comes to interpreting widely differing measurements of destructive storms. For instance, it was only with the advent of weather satellites that a reasonably complete and consistent record of tropical storms could be maintained. Earlier records depended on shore-based and shipping observations, plus an increasing number of aircraft measurements from the 1940s, all of which relied on different types of equipment and provided only partial mapping of storms around the world. All of this means that any long climatic series must be subjected to close scrutiny to ensure that what appear to be significant changes are a real part of the larger climate and not due to changes in the equipment, observing practices or the site itself.
The history of the study of climate change has been principally a matter of painstaking and scholarly detective work to establish the reliability and applicability of the data.
Global Producing Centers of Long-Range Forecasts (GPCs)
Global Producing Centres are WMO-certified centres, that assist WMO Members by providing operational long-range forecasts on the global scale as input for regional and national climate services.
Climate change and its potential impacts have boosted social demands for tailored climate services. By the same time, advances in science and technology provide a multitude of opportunities to build up sustained routines for such services. In order to meet WMO Members needs in enhanced service delivery capacities, a worldwide 3-level-structure has been implemented with the National Meteorological and Hydrological Services acting on the national scale, Regional Climate Centres providing regional, continent-wide climate information and services and Global Producing Centres delivering global scale information and services.
The complex nature of the Earths climate system with processes like El Niño, with strong potentials of influencing climate patterns around the world, requires a systematic approach in order to forecast its behavior. Global predictions covering phenomena like El Niño set the frame, essentially needed for regional and local predictions. The process of computing long-range forecasts (forecast range from 30 days up to two years) on the global scale requires huge amounts of computer power along with a very specialized knowledge. Hence, provision of global scale services by some global centres enable WMO Members to focus their capacities on the local end user in order to provide best possible climate prediction services.
Global Producing Centres Centres are proposed by WMO Member States and follow a strict designation process through the WMOs Technical Commissions for Climatology (CCl) and Basic Systems (CBS).
Through this designation process, GPCs adhere to certain well-defined standards aiding consistency and usability of output:
a fixed forecast production cycle
a standard set of forecast products
WMO-defined verification standards (for retrospective forecasts)
A comprehensive set of standard verification measures, with which to communicate the skill of forecasts, has also been defined (the WMO Standard Verification System for Long-Range Forecasts SVSLRF).
The primary users of an GPC are Regional Climate Centres, the National Meteorological and Hydrological Services (NMHSs) and other GPCs including Lead Centres for the Standardised Verification System for Long-range Forecasts (Melbourne and Montreal) as well as for Long-range forecast multi-model ensemble (Seoul and NOAA/NCEP).
RCCs and NMHSs typically use GPC products as input for their Long-range Forecasting services vis-à-vis their end user community. Especially RCCs and RCOFs use global scale products to apply downscaling methods or Regional Climate Models to compute more precise predictions for certain regions. It is, however, important to note, that NMHSs retain the mandate and authority to provide the liaison with national user groups, and to issue advisories and warnings.
Regional Climate Centres
Regional Climate Centres are Centres of Excellence that assist WMO Members in a given region to deliver better climate services and products including regional long-range forecasts, and to strengthen their capacity to meet national climate information needs. Climate change and its potential impacts have boosted social demands for tailored climate services. By the same time, advances in science and technology provide a multitude of opportunities to build up sustained routines for such services. Constant scientific progress increases humankinds understanding and provides societies with more and more complex approaches. Accelerated technical advances offer to develop and run more and more sophisticated tools.
Climate analyses as well as seasonal and climate forecasting provide excellent examples of this evolution. Related research and operation requires huge amounts of resources in terms of, e.g. computer power, model research and know-how, IT expertise as well as interpretation capabilities. Therefore, networking and international specialization becomes more and more necessary. By the same time, this approach has a huge potential in terms of sustainability.
The concept of Regional Climate Centres offers excellent opportunities for networking by pooling certain capacities of the NMHSs and other institutes in a region by an efficient systems approach. Accordingly, each Member in a region gets sustained, operational access to the most updated climate services. Beyond that, political and economical structures get more and more transnational, and hence require regional services, which RCCs are mandated to deliver through the NMHSs. Regional services are also needed to set a context for national activities. Eventually, climate events affecting two or more national territories require regional mechanisms to ensure its proper analyses.
The primary users of an RCC are the National Meteorological and Hydrological Services (NMHSs) and other RCCs in the region and in neighboring areas. NMHSs typically use RCC products to extend or improve their service suite vis-à-vis their end user community. Only if NMHSs in a region unanimously require and agree, RCCs might serve end users directly. It is, however, important to note, that RCC responsibilities should be regional in nature and not duplicate or replace those of NMHSs. NMHSs retain the mandate and authority to provide the liaison with national user groups, and to issue advisories and warnings.
Consensus-driven predictions and outlooks
Regional Climate Outlook Forums (RCOFs)
In the late 1990s, an innovative process known as the Regional Climate Outlook Forum (RCOF) was initiated by WMO, National Meteorological and Hydrological Services (NMHSs), regional institutions, and other international organizations. It is a forum that brings together the experts from a climatologically homogeneous region and provides consensus-based, climate prediction and information usually for the season having critical socio-economic significance. This information has been applied to reducing climate-related risks and supporting sustainable development. Such forums have spread to many regions across the world.
Concept
These forums bring together national, regional and international climate experts, on an operational basis, to produce regional climate outlooks based on input from NMHSs, regional institutions, Regional Climate Centres (RCCs) and global producers of climate predictions. By bringing together countries having common climatological characteristics, the forums ensure consistency in the access to and interpretation of climate information. Through interaction with sectoral users, extension agencies and policy makers, RCOFs assess the likely implications of the outlooks on the most pertinent socio-economic sectors in the given region and explore ways how these outlooks could be used.
The core concept of all the RCOFs remains the same: delivering consensus-based user-relevant climate outlook products in real time through regional cooperation and partnership. However, since national and regional capacities are varied and, in some cases, are inadequate to face the task individually, the implementation mechanisms of the RCOFs in different regions have been tailored to meet the local conditions.
The RCOF process, pioneered in Africa, typically includes the following components:
Meetings of the regional and international climate experts to develop a consensus for the regional climate outlook, typically in a probabilistic form;
The Forum proper, that involves both climate scientists and representatives from the user sectors, for identification of impacts and implications, and the formulation of response strategies;
A training workshop on seasonal climate prediction to strengthen the capacity of the national and regional climate scientists;
Special outreach sessions involving media experts, to develop effective communications strategies.
RCOFs also review impediments to the use of climate information, experiences and successful lessons regarding applications of the past RCOF products, and enhance sector-specific applications. These RCOFs then lead to national forums to develop detailed national-scale climate outlooks and risk information including warnings for communication to decision-makers and the public.
RCOFs have facilitated regional cooperation and networking, and have effectively demonstrated the immense mutual benefits of sharing of climate information and experience. Close interaction between the providers and users of climate information and predictions has enhanced feedback from the users to climate scientists, and has catalyzed the development of many user-specific products.
RCOF Users
In many regions, the users benefiting from the RCOFs are true stakeholders, contributing to the organization and growth of the sessions, thus ensuring their sustainability, and applicability to meeting user needs. Typically, RCOFs attract the participation of practitioners and decision-makers from sectors including:
Agriculture and food security
Water resources
Energy production and distribution
Public health
Disaster risk reduction and response
Outreach and communication
Other sectors such as tourism, transportation, urban planning, etc. are increasingly involved.
Based on the needs of specific sectors, specialized, sector-oriented outlook forums, such as the Malaria Outlook Forums (MALOFs) are being held in conjunction with RCOFs in Africa.
RCOFs are in operation in many parts of the world, mainly serving developing countries. These are:
GHACOF: Greater Horn of Africa COF
SARCOF: Southern Africa COF
PRESAO: Prévision Saisonnière en Afrique de lOuest
PRESAC: Prévision Saisonnière en Afrique Centrale
FOCRAII: Forum on Regional Climate Monitoring, Assessment and Prediction for Regional Association II (Asia)
SSACOF: Southeast of South America COF
WCSACOF: Western Coast of South America COF
CCOF: Caribbean COF
FCCA: Foro Regional del Clima de América Central
PICOF: Pacific Islands COF
SEECOF: SouthEastern Europe COF
Regional Climate Change and RCOFs
RCOFs were originally conceived to focus on seasonal prediction, and have significantly contributed to adaptation to climate variability. The concept has the potential to be extended to develop our capacity to adapt to climate change. RCOFs can be effectively expanded to cater to the needs of developing and disseminating regional climate change information products. This concept is already being tested by some RCOFs (e.g., GHACOF). Regional assessments of observed and projected climate change, including the development of downscaled climate change scenario products for impact assessments, can be included in the product portfolio of RCOFs. This potential has already been recognized by the United Nations Framework Convention on Climate Change (UNFCCC) Subsidiary Body on Science and Technology Advice (SBSTA), and constitutes a key element of WMOs contribution to the Nairobi Work Programme on impacts, vulnerability and adaptation to climate change.
Climate Watch and Alert Systems
Inter-annual variations can affect global and regional atmospheric and oceanic circulation. Many of these variations are recurrent and are usually depicted with well known climatic patterns such as the El Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), warming/cooling of Sea Surface Temperatures (SST) in the tropical oceans, strengthening/weakening of the upper level Jets, etc. They correlate significantly with the departures from the mean state of climate parameters at monthly, seasonal and annual time scales and with the onset of extreme weather and climate events leading to direct and indirect consequences on lives, goods, properties and the well being of societies. Droughts, heat waves, cold waves, flooding, extreme wind storms, land slides, bush and forest fires, costal erosions to list just these are the most popular induced impacts which may be triggered by one or several of such anomalies. In the context of global warming these extremes are expected to become in the future more frequent, more severe and gaining more geographical extend than usually known (IPCC AR4). Some of the observed increase in climate extremes already fit in these projections.
Setting up an effective Climate Watch System for climate extremes has been for more than a decade a focus of the WMO and the National Meteorological and Hydrological Services (NMHSs) to improve climate risk management capabilities among nations. Such climate warning system e.g. climate watch systems are designed to provide advisories (climate watches) to inform the users, particularly those involved in natural hazards preparedness, mitigation and response on ongoing, pending and/or expected climate anomalies and their negative impacts. To this effect, NMHSs should be adequately equipped and prepared to continuously monitor and assess the state of the climate, evaluate available long range forecasts, and where conditions warrant provide to the users concise and understandable climate early warning information at weekly, 10-day, monthly, and seasonal time scale.
With adequate measurements of the climatic conditions covering many years, it is possible to define what is considered normal and what is an extreme event for any part of the world. Data gathered over the 30-year period from 1961 to 1990 define the latest Normals used for climate reference. At any given time of the year, an extreme high temperature might be defined as one that occurs only once in every 30 years. A cold winter or hot summer can be specified in a similar way, or in terms of the number of days below or above defined exceptional values. This means that when there is a succession of extremes, or more extreme events over a period (e.g. season), it is possible to estimate whether they seem to be part of the normal expectation for the locality, or are so unlikely that they can only be explained in terms of some more radical shift in the climate. The basic properties of any data
series, for example temperature, can be defined in terms of the mean over time and the amount of variance about the mean.
Other meteorological variables exhibit more complicated statistical properties. For instance,
rainfall is episodic. In many parts of the world, much of the annual rainfall falls in a short rainy season. In addition, most of that rain may be concentrated in a few heavy falls and small shifts in the large-scale weather patterns from year to year may significantly alter the amount and distribution of seasonal rainfall. More complex techniques usually are needed to interpret variations in rainfall.
Trusting climate statistics
Handling the statistics of rare events is of particular importance because we are so vulnerable to extreme weather. There is, for example, a special need to have reliable measurements over as long a time as possible, in order to build up a reliable set of statistics for what are inherently rare events. One complicating factor can arise from changes at the site where the measurements were made and in the instruments used. One well-known site problem results from the expansion of urban areas around an observatory. Urbanization changes many characteristics of the local climate, notably the replacement of cooling trees with concrete and asphalt that heat up during the day but cool only slowly at night.
Buildings and structures also change the ground-level wind flow and create eddies. Urbanization can also lead to rapid rainfall runoff and increases in flash flooding. In rural areas the smaller shifts that may occur are more difficult to detect. For instance, the growth of trees around a farmstead that maintains a weather station alters the local wind flow and temperature patterns, and so reduces extreme wind speeds and the incidence of frosts (where they occur). The trend in the observations reflects the change of the microclimate of the farmstead but the general climate may not have changed. Greater challenges arise when it comes to interpreting widely differing measurements of destructive storms. For instance, it was only with the advent of weather satellites that a reasonably complete and consistent record of tropical storms could be maintained. Earlier records depended on shore-based and shipping observations, plus an increasing number of aircraft measurements from the 1940s, all of which relied on different types of equipment and provided only partial mapping of storms around the world. All of this means that any long climatic series must be subjected to close scrutiny to ensure that what appear to be significant changes are a real part of the larger climate and not due to changes in the equipment, observing practices or the site itself.
The history of the study of climate change has been principally a matter of painstaking and scholarly detective work to establish the reliability and applicability of the data.
Global Producing Centers of Long-Range Forecasts (GPCs)
Global Producing Centres are WMO-certified centres, that assist WMO Members by providing operational long-range forecasts on the global scale as input for regional and national climate services.
Climate change and its potential impacts have boosted social demands for tailored climate services. By the same time, advances in science and technology provide a multitude of opportunities to build up sustained routines for such services. In order to meet WMO Members needs in enhanced service delivery capacities, a worldwide 3-level-structure has been implemented with the National Meteorological and Hydrological Services acting on the national scale, Regional Climate Centres providing regional, continent-wide climate information and services and Global Producing Centres delivering global scale information and services.
The complex nature of the Earths climate system with processes like El Niño, with strong potentials of influencing climate patterns around the world, requires a systematic approach in order to forecast its behavior. Global predictions covering phenomena like El Niño set the frame, essentially needed for regional and local predictions. The process of computing long-range forecasts (forecast range from 30 days up to two years) on the global scale requires huge amounts of computer power along with a very specialized knowledge. Hence, provision of global scale services by some global centres enable WMO Members to focus their capacities on the local end user in order to provide best possible climate prediction services.
Global Producing Centres Centres are proposed by WMO Member States and follow a strict designation process through the WMOs Technical Commissions for Climatology (CCl) and Basic Systems (CBS).
Through this designation process, GPCs adhere to certain well-defined standards aiding consistency and usability of output:
a fixed forecast production cycle
a standard set of forecast products
WMO-defined verification standards (for retrospective forecasts)
A comprehensive set of standard verification measures, with which to communicate the skill of forecasts, has also been defined (the WMO Standard Verification System for Long-Range Forecasts SVSLRF).
The primary users of an GPC are Regional Climate Centres, the National Meteorological and Hydrological Services (NMHSs) and other GPCs including Lead Centres for the Standardised Verification System for Long-range Forecasts (Melbourne and Montreal) as well as for Long-range forecast multi-model ensemble (Seoul and NOAA/NCEP).
RCCs and NMHSs typically use GPC products as input for their Long-range Forecasting services vis-à-vis their end user community. Especially RCCs and RCOFs use global scale products to apply downscaling methods or Regional Climate Models to compute more precise predictions for certain regions. It is, however, important to note, that NMHSs retain the mandate and authority to provide the liaison with national user groups, and to issue advisories and warnings.
Regional Climate Centres
Regional Climate Centres are Centres of Excellence that assist WMO Members in a given region to deliver better climate services and products including regional long-range forecasts, and to strengthen their capacity to meet national climate information needs. Climate change and its potential impacts have boosted social demands for tailored climate services. By the same time, advances in science and technology provide a multitude of opportunities to build up sustained routines for such services. Constant scientific progress increases humankinds understanding and provides societies with more and more complex approaches. Accelerated technical advances offer to develop and run more and more sophisticated tools.
Climate analyses as well as seasonal and climate forecasting provide excellent examples of this evolution. Related research and operation requires huge amounts of resources in terms of, e.g. computer power, model research and know-how, IT expertise as well as interpretation capabilities. Therefore, networking and international specialization becomes more and more necessary. By the same time, this approach has a huge potential in terms of sustainability.
The concept of Regional Climate Centres offers excellent opportunities for networking by pooling certain capacities of the NMHSs and other institutes in a region by an efficient systems approach. Accordingly, each Member in a region gets sustained, operational access to the most updated climate services. Beyond that, political and economical structures get more and more transnational, and hence require regional services, which RCCs are mandated to deliver through the NMHSs. Regional services are also needed to set a context for national activities. Eventually, climate events affecting two or more national territories require regional mechanisms to ensure its proper analyses.
The primary users of an RCC are the National Meteorological and Hydrological Services (NMHSs) and other RCCs in the region and in neighboring areas. NMHSs typically use RCC products to extend or improve their service suite vis-à-vis their end user community. Only if NMHSs in a region unanimously require and agree, RCCs might serve end users directly. It is, however, important to note, that RCC responsibilities should be regional in nature and not duplicate or replace those of NMHSs. NMHSs retain the mandate and authority to provide the liaison with national user groups, and to issue advisories and warnings.
Consensus-driven predictions and outlooks
Regional Climate Outlook Forums (RCOFs)
In the late 1990s, an innovative process known as the Regional Climate Outlook Forum (RCOF) was initiated by WMO, National Meteorological and Hydrological Services (NMHSs), regional institutions, and other international organizations. It is a forum that brings together the experts from a climatologically homogeneous region and provides consensus-based, climate prediction and information usually for the season having critical socio-economic significance. This information has been applied to reducing climate-related risks and supporting sustainable development. Such forums have spread to many regions across the world.
Concept
These forums bring together national, regional and international climate experts, on an operational basis, to produce regional climate outlooks based on input from NMHSs, regional institutions, Regional Climate Centres (RCCs) and global producers of climate predictions. By bringing together countries having common climatological characteristics, the forums ensure consistency in the access to and interpretation of climate information. Through interaction with sectoral users, extension agencies and policy makers, RCOFs assess the likely implications of the outlooks on the most pertinent socio-economic sectors in the given region and explore ways how these outlooks could be used.
The core concept of all the RCOFs remains the same: delivering consensus-based user-relevant climate outlook products in real time through regional cooperation and partnership. However, since national and regional capacities are varied and, in some cases, are inadequate to face the task individually, the implementation mechanisms of the RCOFs in different regions have been tailored to meet the local conditions.
The RCOF process, pioneered in Africa, typically includes the following components:
Meetings of the regional and international climate experts to develop a consensus for the regional climate outlook, typically in a probabilistic form;
The Forum proper, that involves both climate scientists and representatives from the user sectors, for identification of impacts and implications, and the formulation of response strategies;
A training workshop on seasonal climate prediction to strengthen the capacity of the national and regional climate scientists;
Special outreach sessions involving media experts, to develop effective communications strategies.
RCOFs also review impediments to the use of climate information, experiences and successful lessons regarding applications of the past RCOF products, and enhance sector-specific applications. These RCOFs then lead to national forums to develop detailed national-scale climate outlooks and risk information including warnings for communication to decision-makers and the public.
RCOFs have facilitated regional cooperation and networking, and have effectively demonstrated the immense mutual benefits of sharing of climate information and experience. Close interaction between the providers and users of climate information and predictions has enhanced feedback from the users to climate scientists, and has catalyzed the development of many user-specific products.
RCOF Users
In many regions, the users benefiting from the RCOFs are true stakeholders, contributing to the organization and growth of the sessions, thus ensuring their sustainability, and applicability to meeting user needs. Typically, RCOFs attract the participation of practitioners and decision-makers from sectors including:
Agriculture and food security
Water resources
Energy production and distribution
Public health
Disaster risk reduction and response
Outreach and communication
Other sectors such as tourism, transportation, urban planning, etc. are increasingly involved.
Based on the needs of specific sectors, specialized, sector-oriented outlook forums, such as the Malaria Outlook Forums (MALOFs) are being held in conjunction with RCOFs in Africa.
RCOFs are in operation in many parts of the world, mainly serving developing countries. These are:
GHACOF: Greater Horn of Africa COF
SARCOF: Southern Africa COF
PRESAO: Prévision Saisonnière en Afrique de lOuest
PRESAC: Prévision Saisonnière en Afrique Centrale
FOCRAII: Forum on Regional Climate Monitoring, Assessment and Prediction for Regional Association II (Asia)
SSACOF: Southeast of South America COF
WCSACOF: Western Coast of South America COF
CCOF: Caribbean COF
FCCA: Foro Regional del Clima de América Central
PICOF: Pacific Islands COF
SEECOF: SouthEastern Europe COF
Regional Climate Change and RCOFs
RCOFs were originally conceived to focus on seasonal prediction, and have significantly contributed to adaptation to climate variability. The concept has the potential to be extended to develop our capacity to adapt to climate change. RCOFs can be effectively expanded to cater to the needs of developing and disseminating regional climate change information products. This concept is already being tested by some RCOFs (e.g., GHACOF). Regional assessments of observed and projected climate change, including the development of downscaled climate change scenario products for impact assessments, can be included in the product portfolio of RCOFs. This potential has already been recognized by the United Nations Framework Convention on Climate Change (UNFCCC) Subsidiary Body on Science and Technology Advice (SBSTA), and constitutes a key element of WMOs contribution to the Nairobi Work Programme on impacts, vulnerability and adaptation to climate change.
Climate Watch and Alert Systems
Inter-annual variations can affect global and regional atmospheric and oceanic circulation. Many of these variations are recurrent and are usually depicted with well known climatic patterns such as the El Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), warming/cooling of Sea Surface Temperatures (SST) in the tropical oceans, strengthening/weakening of the upper level Jets, etc. They correlate significantly with the departures from the mean state of climate parameters at monthly, seasonal and annual time scales and with the onset of extreme weather and climate events leading to direct and indirect consequences on lives, goods, properties and the well being of societies. Droughts, heat waves, cold waves, flooding, extreme wind storms, land slides, bush and forest fires, costal erosions to list just these are the most popular induced impacts which may be triggered by one or several of such anomalies. In the context of global warming these extremes are expected to become in the future more frequent, more severe and gaining more geographical extend than usually known (IPCC AR4). Some of the observed increase in climate extremes already fit in these projections.
Setting up an effective Climate Watch System for climate extremes has been for more than a decade a focus of the WMO and the National Meteorological and Hydrological Services (NMHSs) to improve climate risk management capabilities among nations. Such climate warning system e.g. climate watch systems are designed to provide advisories (climate watches) to inform the users, particularly those involved in natural hazards preparedness, mitigation and response on ongoing, pending and/or expected climate anomalies and their negative impacts. To this effect, NMHSs should be adequately equipped and prepared to continuously monitor and assess the state of the climate, evaluate available long range forecasts, and where conditions warrant provide to the users concise and understandable climate early warning information at weekly, 10-day, monthly, and seasonal time scale.
