An Update on Trends in Skill of Daily Forecasts of Temperature and Precipitation at the State University of New York at Albany

1983 ◽  
Vol 64 (4) ◽  
pp. 346-354 ◽  
Author(s):  
Lance F. Bosart
Keyword(s):  
New York ◽  
Minimum Temperature ◽  
Linear Regression Analysis ◽  
Precipitation Amount ◽  
The State ◽  
Maximum Temperature ◽  
Daily Maximum ◽  
State University ◽  
Skill Levels ◽  
Temperature And Precipitation

Consensus (the average of all forecasts) skill levels in forecasting daily maximum and minimum temperature, precipitation probability across six class intervals, and precipitation amount at the State University of New York at Albany are reviewed for the period 1977–82. Skill is measured relative to a climatological control. Forecasts are made for four consecutive 24 h periods for Albany, N.Y., beginning at 1800 GMT of the current day. For minimum temperature, the skill levels average 57%, 41%, 26%, and 15%, respectively, for 24, 48, 72, and 96 h in advance. For maximum temperature, a more limited sample yields corresponding skill levels of 84%, 49%, 34%, and 19% for 12, 36, 60, 84 h ahead. Linear regression analysis yields little in the way of a definitive trend, given the smallness of the explained variance. Comparison with other readily available objective and subjective operational guidance establishes the credibility of the consensus forecast.

Detecting climate change in Ukraine: trends, prediction and extreme events

2021 ◽  
Author(s):  
Anna Bohushenko ◽  
Sergiy Stepanenko ◽  
Inna Khomenko
Keyword(s):  
Spatial Distribution ◽  
Minimum Temperature ◽  
Precipitation Amount ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Minimum Value ◽  
Maximum Value ◽  
Temperature Indices ◽  
Consecutive Dry Days

<p>In this study the trends and variations in 25 extreme temperature and precipitation indices<br>defined by ETCCDI, are examined using trend method, probability distribution analysis and<br>spatial statistics for periods of 71 to 137 years for 16 stations evenly distributed in Ukraine. Data<br>on the indices were obtained from www.ecad.eu.<br>Since 1981, temperature has increased by about 1ºC in all stations in question relative to the<br>period of 1945-1980. Analysis of the temperature indices indicates that during the 20th and the<br>beginning of the 21th century there is significant warming which is particularly pronounced in<br>annual mean and annual maximum temperatures. Occurrence of more summer days, warm days<br>and tropical nights and warm spell duration reached the record highest level, and conversely<br>occurrence of frost and ice days, cold days and cold spell duration fall to a record low for the last<br>three decades in the most of study territory.<br>Since 1981, precipitation amount has grown by 30-50 mm relative to the period of 1945-1980 for<br>the most of Ukrainian territory, except Uzhhorod and Uman where precipitation amount has<br>remained the same. For Ukraine average, an increase in maximum daily and maximum 5 days<br>precipitation amount, the maximum number of consecutive wet days, heavy and very heavy<br>precipitation days, and a decrease in the maximum number of consecutive dry days are observed<br>for the last three decades.<br>The analysis of the spatial distribution of trend of precipitation and temperature indices showed<br>that there are large differences between regions of Ukraine, and coherence of spatial distribution<br>of trends of various indices is low.<br>Spectral analysis and harmonic regression techniques were used to derive simulated and<br>predicted (2019-2050) values of annual precipitation and annual mean temperature and four<br>indices such as maximum value of daily maximum temperature, minimum value of daily<br>minimum temperature, the highest 1-day precipitation amount and maximum number of<br>consecutive dry days for some stations such as Kerch (the Crimean Peninsula), Kyiv (situated in<br>north-central Ukraine along the Dnieper River), Lubny (Dnieper Lowland), Lviv and Shepetivka<br>(Podillia Upland), Uzhhorod (Transcarpathia), Uman (Dnieper Upland).<br>Annual mean temperature and maximum value of daily maximum temperature were predicted to<br>increase by 0.33°C per decade in the period of 2019-2050 with respect to 1981-2018, while<br>minimum value of daily minimum temperature was predicted to grow slightly faster (by 0.43-<br>0.63ºC per decade).<br>Precipitation was predicted to increase for the stations in question by 20-66 mm up to 2050<br>relative to 1981-2018 and conversely maximum number of consecutive dry days will slightly<br>decline except Lubny where increase in an aridity index was predicted. In the next three decades<br>changes in maximum daily precipitation will be various: in Shepetivka and Kyiv such<br>precipitation will be decreased and in other stations increasement in such precipitation will be up<br>to 6 mm till 2050 with respect to 1981-2018.</p>

scholarly journals Spatiotemporal Changes in Temperature and Precipitation in West Africa. Part I: Analysis with the CMIP6 Historical Dataset

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3506
Author(s):  
Gandomè Mayeul Leger Davy Quenum ◽  
Francis Nkrumah ◽  
Nana Ama Browne Klutse ◽  
Mouhamadou Bamba Sylla
Keyword(s):  
West Africa ◽  
Minimum Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Upward Trend ◽  
Extreme Climate ◽  
Temperature And Precipitation ◽  
Extreme Indices

Climate variability and change constitute major challenges for Africa, especially West Africa (WA), where an important increase in extreme climate events has been noticed. Therefore, it appears essential to analyze characteristics and trends of some key climatological parameters. Thus, this study addressed spatiotemporal variabilities and trends in regard to temperature and precipitation extremes by using 21 models of the Coupled Model Intercomparison Project version 6 (CMIP6) and 24 extreme indices from the Expert Team on Climate Change Detection and Indices (ETCCDI). First, the CMIP6 variables were evaluated with observations (CHIRPS, CHIRTS, and CRU) of the period 1983–2014; then, the extreme indices from 1950 to 2014 were computed. The innovative trend analysis (ITA), Sen’s slope, and Mann–Kendall tests were utilized to track down trends in the computed extreme climate indices. Increasing trends were observed for the maxima of daily maximum temperature (TXX) and daily minimum temperature (TXN) as well as the maximum and minimum of the minimum temperature (TNX and TNN). This upward trend of daily maximum temperature (Tmax) and daily minimum temperature (Tmin) was enhanced with a significant increase in warm days/nights (TX90p/TN90p) and a significantly decreasing trend in cool days/nights (TX10p/TN10p). The precipitation was widely variable over WA, with more than 85% of the total annual water in the study domain collected during the monsoon period. An upward trend in consecutive dry days (CDD) and a downward trend in consecutive wet days (CWD) influenced the annual total precipitation on wet days (PRCPTOT). The results also depicted an upward trend in SDII and R30mm, which, additionally to the trends of CDD and CWD, could be responsible for localized flood-like situations along the coastal areas. The study identified the 1970s dryness as well as the slight recovery of the 1990s, which it indicated occurred in 1992 over West Africa.

scholarly journals Impact of Aligning Climatological Day on Gridding Daily Maximum–Minimum Temperature and Precipitation over Canada

2011 ◽  
Vol 50 (8) ◽  
pp. 1654-1665 ◽  
Author(s):  
Ron F. Hopkinson ◽  
Daniel W. McKenney ◽  
Ewa J. Milewska ◽  
Michael F. Hutchinson ◽  
Pia Papadopol ◽  
...  
Keyword(s):  
Minimum Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Daily Minimum ◽  
Temperature And Precipitation ◽  
Daily Data ◽  
National University ◽  
Maximum Temperatures

AbstractOn 1 July 1961, the climatological day was redefined to end at 0600 UTC at all principal climate stations in Canada. Prior to that, the climatological day at principal stations ended at 1200 UTC for maximum temperature and precipitation and 0000 UTC for minimum temperature and was similar to the climatological day at ordinary stations. Hutchinson et al. reported occasional larger-than-expected residuals at 50 withheld stations when the Australian National University Spline (ANUSPLIN) interpolation scheme was applied to daily data for 1961–2003, and it was suggested that these larger residuals were in part due to the existence of different climatological days. In this study, daily minimum and maximum temperatures at principal stations were estimated using hourly temperatures for the same climatological day as local ordinary climate stations for the period 1953–2007. Daily precipitation was estimated at principal stations using synoptic precipitation data for the climatological day ending at 1200 UTC, which, for much of the country, was close to the time of the morning observation at ordinary climate stations. At withheld principal stations, the climatological-day adjustments led to the virtual elimination of large residuals in maximum and minimum temperature and a marked reduction in precipitation residuals. Across all 50 withheld stations the climatological day adjustments led to significant reductions, by around 12% for daily maximum temperature, 15% for daily minimum temperature, and 22% for precipitation, in the residuals reported by Hutchinson et al.

scholarly journals Optimizing Input Data for Gridding Climate Normals for Canada

2012 ◽  
Vol 51 (8) ◽  
pp. 1508-1518 ◽  
Author(s):  
Ron F. Hopkinson ◽  
Michael F. Hutchinson ◽  
Daniel W. McKenney ◽  
Ewa J. Milewska ◽  
Pia Papadopol
Keyword(s):  
Minimum Temperature ◽  
Spatial Models ◽  
Maximum Temperature ◽  
Smoothing Spline ◽  
Daily Maximum ◽  
Minimal Amount ◽  
Temperature And Precipitation ◽  
Regression Relationship ◽  
National University

AbstractSpatial models of 1971–2000 monthly climate normals for daily maximum and minimum temperature and total precipitation are required for many applications. The World Meteorological Organization’s recommended standard for the calculation of a normal value is a complete 30-yr record with a minimal amount of missing data. Only 650 stations (~16%) in Canada meet this criterion for the period 1971–2000. Thin-plate smoothing-spline analyses, as implemented by the Australian National University Splines (ANUSPLIN) package, are used to assess the utility of differing amounts of station data in estimating nationwide monthly climate normals. The data include 1) only those stations (1169) with 20 or more years of data, 2) all stations (3835) with 5 or more years of data in at least one month, and 3) as in case 2 but with data adjusted through the most statistically significant linear-regression relationship with a nearby long-term station to 20 or more years (3983 stations). Withheld-station tests indicate that the regression-adjusted normals as in dataset 3 generally yield the best results for all three climatological elements, but the unadjusted normals as in dataset 2 are competitive with the adjusted normals in spring and autumn, reflecting the known longer spatial correlation scales in these seasons. The summary mean absolute differences between the ANUSPLIN estimates and the observations at 48 spatially representative withheld stations for dataset 3 are 0.36°C, 0.66°C, and 4.7 mm, respectively, for maximum temperature, minimum temperature, and precipitation. These are respectively 18%, 7%, and 18% smaller than the summary mean absolute differences for the long-term normals in dataset 1.

scholarly journals Effects of Cropland Expansion on Temperature Extremes in Western India from 1982 to 2015

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 489
Author(s):  
Jinxiu Liu ◽  
Weihao Shen ◽  
Yaqian He
Keyword(s):  
Land Use ◽  
Heat Flux ◽  
Land Cover ◽  
Minimum Temperature ◽  
Negative Impact ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum ◽  
Temperature Extremes ◽  
Western India

India has experienced extensive land cover and land use change (LCLUC). However, there is still limited empirical research regarding the impact of LCLUC on climate extremes in India. Here, we applied statistical methods to assess how cropland expansion has influenced temperature extremes in India from 1982 to 2015 using a new land cover and land use dataset and ECMWF Reanalysis V5 (ERA5) climate data. Our results show that during the last 34 years, croplands in western India increased by ~33.7 percentage points. This cropland expansion shows a significantly negative impact on the maxima of daily maximum temperature (TXx), while its impacts on the maxima of daily minimum temperature and the minima of daily maximum and minimum temperature are limited. It is estimated that if cropland expansion had not taken place in western India over the 1982 to 2015 period, TXx would likely have increased by 0.74 (±0.64) °C. The negative impact of croplands on reducing the TXx extreme is likely due to evaporative cooling from intensified evapotranspiration associated with croplands, resulting in increased latent heat flux and decreased sensible heat flux. This study underscores the important influences of cropland expansion on temperature extremes and can be applicable to other geographic regions experiencing LCLUC.

scholarly journals Joint Occurrence of Daily Temperature and Precipitation Extreme Events over Canada

2014 ◽  
Vol 53 (9) ◽  
pp. 2148-2162 ◽  
Author(s):  
Bárbara Tencer ◽  
Andrew Weaver ◽  
Francis Zwiers
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Heavy Precipitation ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Negative Consequences ◽  
Temperature And Precipitation ◽  
Joint Occurrence

AbstractThe occurrence of individual extremes such as temperature and precipitation extremes can have a great impact on the environment. Agriculture, energy demands, and human health, among other activities, can be affected by extremely high or low temperatures and by extremely dry or wet conditions. The simultaneous or proximate occurrence of both types of extremes could lead to even more profound consequences, however. For example, a dry period can have more negative consequences on agriculture if it is concomitant with or followed by a period of extremely high temperatures. This study analyzes the joint occurrence of very wet conditions and high/low temperature events at stations in Canada. More than one-half of the stations showed a significant positive relationship at the daily time scale between warm nights (daily minimum temperature greater than the 90th percentile) or warm days (daily maximum temperature above the 90th percentile) and heavy-precipitation events (daily precipitation exceeding the 75th percentile), with the greater frequencies found for the east and southwest coasts during autumn and winter. Cold days (daily maximum temperature below the 10th percentile) occur together with intense precipitation more frequently during spring and summer. Simulations by regional climate models show good agreement with observations in the seasonal and spatial variability of the joint distribution, especially when an ensemble of simulations was used.

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