  Jet energy scale measurements and their systematic uncertainties are reported
for jets measured with the ATLAS detector using proton-proton collision data
with a center-of-mass energy of $\sqrt{s} = 13$ TeV, corresponding to an
integrated luminosity of 3.2 fb$^{-1}$ collected during 2015 at the LHC. Jets
are reconstructed from energy deposits forming topological clusters of
calorimeter cells, using the anti-$k_{t}$ algorithm with radius parameter $R =
0.4$. Jets are calibrated with a series of simulation-based corrections and in
situ techniques. In situ techniques exploit the transverse momentum balance
between a jet and a reference object such as a photon, $Z$ boson, or multijet
system for jets with $20 < p_{T} < 2000$ GeV and pseudorapidities of
$|\eta|<4.5$, using both data and simulation. An uncertainty in the jet energy
scale of less than 1% is found in the central calorimeter region ($|\eta| <
1.2$) for jets with $100 < p_{T} < 500$ GeV. An uncertainty of about 4.5% is
found for low-$p_{T}$ jets with $p_{T} = 20$ GeV in the central region,
dominated by uncertainties in the corrections for multiple proton-proton
interactions. The calibration of forward jets ($|\eta| > 0.8$) is derived from
dijet $p_{T}$ balance measurements. For jets of $p_{T} = 80$ GeV, the
additional uncertainty for the forward jet calibration reaches its largest
value of about 2% in the range $|\eta| > 3.5$ and in a narrow slice of $2.2 <
|\eta| < 2.4$.
