TY  - GEN
A1  - Kumar, Rohini
A1  - Hesse, Fabienne
A1  - Rao, P. Srinivasa
A1  - Musolff, Andreas
A1  - Jawitz, James
A1  - Sarrazin, Francois
A1  - Samaniego, Luis
A1  - Fleckenstein, Jan H.
A1  - Rakovec, Oldrich
A1  - Thober, S.
A1  - Attinger, Sabine
T1  - Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1352 
KW  - travel time distributions
KW  - groundwater vulnerability
KW  - flux tracking
KW  - transit-time
KW  - water age
KW  - nitrogen
KW  - model
KW  - dynamics
KW  - pollution
KW  - patterns
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-549875
SN  - 1866-8372
IS  - 1
ER  - 
TY  - JOUR
A1  - Kumar, Rohini
A1  - Hesse, Fabienne
A1  - Rao, P. Srinivasa
A1  - Musolff, Andreas
A1  - Jawitz, James
A1  - Sarrazin, Francois
A1  - Samaniego, Luis
A1  - Fleckenstein, Jan H.
A1  - Rakovec, Oldrich
A1  - Thober, S.
A1  - Attinger, Sabine
T1  - Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe
JF  - Nature Communications
N2  - Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes.
KW  - travel time distributions
KW  - groundwater vulnerability
KW  - flux tracking
KW  - transit-time
KW  - water age
KW  - nitrogen
KW  - model
KW  - dynamics
KW  - pollution
KW  - patterns
Y1  - 2020
U6  - https://doi.org/10.1038/s41467-020-19955-8
SN  - 2041-1723
VL  - 11
IS  - 1
SP  - 1
EP  - 10
PB  - Nature Publishing Group UK
CY  - London
ER  - 
TY  - JOUR
A1  - Borck, Rainald
A1  - Tabuchi, Takatoshi
T1  - Pollution and city size: can cities be too small?
JF  - Journal of Economic Geography
N2  - We study optimal and equilibrium sizes of cities in a city system model with pollution. Pollution is a function of population size. If pollution is local or per-capita pollution increases with population, equilibrium cities are too large under symmetry; with asymmetric cities, the largest cities are too large and the smallest too small. When pollution is global and per-capita pollution declines with city size, cities may be too small under symmetry; with asymmetric cities, the largest cities are too small and the smallest too large if the marginal damage of pollution is large enough. We calibrate the model to US cities and find that the largest cities may be undersized by 3-4%.
KW  - Optimal city size distribution
KW  - agglomeration
KW  - pollution
Y1  - 2018
U6  - https://doi.org/10.1093/jeg/lby017
SN  - 1468-2702
SN  - 1468-2710
VL  - 19
IS  - 5
SP  - 995
EP  - 1020
PB  - Oxford Univ. Press
CY  - Oxford
ER  -