ORIGINAL PAPER Temperature difference relationship among precipitation, dry days, and spells in Turkey Ismail Dabanli 1,2 Received: 3 April 2017 /Accepted: 28 September 2018 # Springer-Verlag GmbH Austria, part of Springer Nature 2018 Abstract Strong logical relationships exist between temperature difference and hydro-meteorological variables such as precipita- tion, dry days, and dry spells. These relationships can be used for knowing how the differences of total and top 10% heavy precipitations, dry days, and dry spells will change with respect to temperature differences? Here, daily precip- itation and temperature records over Turkey are considered from 1971 to 2010, inclusive. First 30-year (1971–2000) data are used for training for temperature difference function (ΔT) and the remaining 10-year (2001–2010) is reserved for validation. The temperature difference function is validated by mean relative error, and the results are calculated for total and top 10% heavy precipitation, dry days, and spells as 14.60%, 6.14%, 2.81%, and 11.89%, respectively. The strong relationship exists between temperature difference function and standard deviation of corresponding climatic variables. Results show that standard deviation and mean relative error (MRE) have linear correlation. Also, ΔT model predictions are compared with CMIP5 RCPs projections from 2020 to 2100. The suggested model predictions fall within the range of various atmosphere-ocean global circulation (climate) model (AOGCM) scenario RCP 4.5 and RCP 8.5 projections, in addition to model predictions cross-correlation for RCP 2.6 and RCP 6.0. 1 Introduction Climate change is known as consequences of gradually in- creasing air temperature that affects extensive regions all over the world. Increases in extreme events (flood, drought, heat waves, heavy precipitation) aroused great interest on climate change (Dabanl ı and Şen 2018; Mohorji et al. 2017; Laflamme et al. 2015; Chen et al. 2012). Main effect of global warming can be seen on temperature increase at the low latitudes, while warm and dry conditions prevail in the sub-tropic regions (Şen et al. 2017). The heavy precipitations have increasing tendencies on middle latitudes, which are supported by the last IPCC report (2014). Temperature anomaly can be directly linked to several hydro-climatic var- iables such as precipitation, dry days, dry spells, and drought. Climate change impact prediction and analysis researches are increasing for identification of future condi- tion in hydro-climatic variables. For instance, Aziz et al. (2018) attempt to determine future trends of two IPCC Representative Concentration Pathways (RCPs) 4.5 and 8.5 emission scenarios. Similarly, Diasso and Abiodun (2018) try to explain future reforestation impacts on drought inci- dences. Not only future projections, but also observation- based models try to explain general behaviors of hydro- climatic variations. For instance, based on observation data, winter droughts are modeled by Meng et al. (2018). The Mediterranean region and European countries are the most heavily vulnerable areas to climate change (Garcia-Ruiz et al. 2011), and currently they are facing an apparent mean annual temperature rise in the forms of dry days and spells, which are considered among the main drought indices (Şen 2014). Based on the temporal analysis of drought, several researchers indicate that Mediterranean countries are more frequently subjective to drought circumstances over recent decades (Vicente-Serrano et al. 2004; Piccarreta et al. 2004; Sousa et al. 2011). It is also observed that due to the climate change, annual mean temperature has been increasing signif- icantly since the last four decades. Turkey, as a Mediterranean country, is facing serious effects of warmer seasons than be- fore and extreme flooding hazards on different regions. * Ismail Dabanli idabanli@medipol.edu.tr 1 School of Engineering and Natural Sciences, Civil Engineering Department, Istanbul Medipol University, Kavacık, Istanbul, Turkey 2 Climate Change Researches Application and Research Center, (IKLIMER), Istanbul Medipol University, Kavacık, Istanbul, Turkey Theoretical and Applied Climatology https://doi.org/10.1007/s00704-018-2649-4